Related
I have this link:
The Best Page
The ajax-populated and -revealed element that exists within the current page is an "enhancement" and has aria-hidden="true". It would be preferable for screen-readers and assistive tech to follow the link's href to the subsequent static page, rather than triggering the click handler (especially since the element that it will acts on is already hidden, as previously mentioned).
Will this behavior already take place or do I need to add something?
When pressing enter on a link, it does the same as a click, and it's a very bad idea to intercept the enter key in order to do something different.
There are keyboard users, perfectly sighted, who aren't using screen reader. These users will experience an unexpected behavior.
Screen readers may choose to send directly a click event, rather than keyboard events, even though enter has been actually pressed. So idem in the opposite direction.
There may be other ways to activate a link, other than click or enter: spacebar, tap on touch screen, assistive techs to click by winking the eyes, etc. How it should behave in these cases ?
By the way, you can't do something different based on whether a screen reader is used or not, simply because you have no 100% reliable way to detect it.
The questions you should ask yourself are:
Why do you want a different behavior between click and enter ? or between screen reader and normal users ?
Are you trying to work around inaccessible content, or do you have two versions of the same content (an accessible and a unaccessible one) ? In that case, it would be much better to have a single content and make it accessible. Rare are the cases where it's really impossible, and experience shows that the two versions are eventually going to be out of sync, more quicker than you think.
Often times convention is one of the most important design consideration for user interface. Usually the advice goes to do it like Microsoft does.
This is for three reasons:
If it ain't broke, don't fix it.
If your users expect to click on a floppy disk icon to save, don't change the icon (even though some of them may have never seen an actual floppy disk).
Users don't want to re-learn the interface (and hot keys, etc.) with each different application they use.
At the same time Emmerson said "*A foolish consistency is the hobgoblin of little minds.*" So when does maintaining a consistent user interface cross the line from a good idea to stagnated innovation?
Microsoft shook up the good old WIMP GUI with the introduction of the tool bar, and then again with the Ribbon control (which is the natural evolution of the tool bar, like it or not.) Now we are seeing ribbons everywhere.
So my question is, what are some user interface paradigms that are accepted and consistent across multiple applications, but have stayed past their prime and are starting to reek? Are there some important changes that would benefit from a grass roots push by developers to innovate and improve the user interface experience for our users?
One thought that came to mind for me is the modal pop-up dialog. You know the ones that say: "Are you sure you want to . . .. - [Yes] [No] [Cancel] [Maybe]" and its evil twin "Successfully completed what you wanted to do! [OK]." We are seeing a movement away from these with the "info panel" in browsers. I think they need to be adopted in windows application development as well.
If possible please list a solution for each stale UI item.
And please don't list clippy. We all know he was a bad idea.
NOTE: This is specifically Windows client user interface paradigms, but I am certainly open to drawing inspiration from the web, the Mac, etc.
You mentioned popup modal dialogs , and I'd argue that non-modal ones are just as bad. Any dialog box remove focus from the program, they could end up behind the program and make it hard to find it, they might not even appear on the same virtual screen.
I'd like to see an end to all dialog boxes. If you need to stop someone from using the UI because of some non-normal circumstance, then remove the relevant parts of the UI from the window, and replace it with what the dialog would contain. Bring back the UI once the problem has been handled.
Clicking things on touch interfaces
It's incredibly difficult to click on things on a touch interface, because you don't know when you have pressed the screen hard enough. And if you add an animation to the button you are clicking, you most likely wont see it, because your finger is in the way. Adding other reactions, like vibrating the phone or painting waves on the screen might work, but there is usually a delay which is too large, much larger than the tactile sense of a button being pressed. So until they invent a screen with buttons that can be pressed, all touch devices should move towards dragging user interfaces (DUIs) instead.
Counter intuitively it is easier to press an object on the screen, drag it, and then release it than it is to just press and release it. It's probably because you can see the object moving when you start dragging, and you can adjust the pressure while dragging it. Dragging also has a lot more options, because you now have a direction, not just a point that you clicked. You can do different things if the user drags the object in different directions. Speed might also be used, as well as the point where the user releases the object. The release point is the real strength of DUIs, because it is very easy to release something, even with pixel precession.
Some designs have started to use DUIs, like (here we go) the iPhone, palm pre and android phones. But only part of their design is DUI, the rest is clicking. One area they all have in common is the keyboard. Instead of clicking on a key the user presses any key, then drags their finger towards the key they really wanted to click. Unlocking these phones also uses dragging.
Other easily implemented DUI features would be things like mouse gestures, where dragging in different directions, or drawing different shapes does different things. There are also alternate keyboards being researched which puts a bigger emphasis on dragging. All buttons can be changed into switches, so have to drag them down a bit to click them. With a well designed graphics, this should be intuitive to the user as well.
The Apple Human Interface Guidelines are a good read on this topic. They discuss this from a very broad point of view and the guidelines apply to any platform, not only Mac.
The file system. I want to save a file.. >OOOPs I need to think of a file name first. Well.... how about ... blah.doc.
6 months later...
Where the %#*(%& * did I save that %()#*()*ing file?
The solution is build a versioning system into the application, or better, the OS. Make files findable by their content, with a search engine, instead of forcing the user to come up with a memorable name, when all they want is for their file to not get lost.
Eliminate the save step. Type something in to the application, and it's just there, and there's no risk of losing it by some misstep, like forgetting to save. If you want an older version, you can just pick a date and see what the document looked like back then.
To build on the search engine idea: It's a pain having to navigate some arbitrary tree structure to find your stuff. Searching is much easier. However, you might still want to have something like a "folder" to group multiple files together. Well, you can build a richer metadata system, and have a "category" or "project" field, and setup the search engine to show items by project, or by category. Or group by those, or whatever new UI discovery we make next.
This question is a bit too open-ended, IMHO.
However, my main approach when designing anything is:
Fits in to wherever it is. If it's a windows app, I copy MS as much as a possible
It's simple.
It provides options
Buttons have a nice description of what the result of clicking will be, as opposed to 'yes or 'no'
Harder to answer the rest of your post without spending hours typing out an arguably useless (and repeated) set of guidelines.
In my mind, the one thing that really stands out is that USERS need more and easier control over the application's user interface appearance and organization.
So many interfaces can not be modified by the user so that the most used/favorite functions can be grouped together. This ability would make your favorite software even easier for you to get things done.
Error messages need a "Just do it!" button.
Seriously, I really don't care about your stupid error message, just DO WHAT I TOLD YOU TO DO!!!
I think the entire Document model of the web needs to change. It's not a user interface, but it leads to many, many bad user interfaces.
The document model was a good idea to connect a bunch of documents, but now the web is also a collection of applications. Today, I think the Page/document model corrupts our thinking. We end up lumping things together that aren't related, modularizing our code wrong, and in the end confusing users with our monolithic control board type websites.
Find dialogs that sit over the widget in which you are doing the search are terrible. Loads of apps do that. The find bar in Firefox works much better.
Many applications have multiple panes within the UI - eg in Outlook there's the preview pane and the inbox pane (amongst others). In these applications typically cursor key presses apply to the currently focussed pane. But there's very poor hinting to show the user which pane has focus and there are seldom keyboard shortcuts to move the focus between panes.
The focussed pane should be highlighted somehow.
Something like alt+cursor keys should move the focus around.
Ctrl-Tab and Ctrl-Shift-Tab cycle left and right through tabs instead of MRU behavior, even though in most cases the same behavior is duplicated with Ctrl-PageUp and Ctrl-PageDown.
There are a lot but here's an idea for a couple of them:
Remove some clicks like in "add another" or "search item" and the like.
This is well done with interfaces like ajax which have autocompletes ( and auto search ) but is slowly being adopted for platform UI's ( and in some cases they were originated in platform UI's. )
This is how StackOverflow does it for some scenarios.
But of course, we all know that already don't we? No need for "Seach tag" or "Add another tag" buttons, they just happen
Dialogs as you described.
Guys at Humanized proposed Transparent messages which actually are used in their product Enso and some other places.
Mac uses them for notifications ( like in Growl ) use them very well, or Ubuntu new notification system.
alt text http://blogs.sun.com/plamere/resource/NowPlayingGrowl.png
Firefox replaces the traditional "Search" dialog box with a search bar at the bottom.
Although not everyone likes the placement for next/previous as in this screenshot
And even SO ( again ) :) replace the notification with the yellow bar.
Finally:
File managers
I really like ( sometimes ) the simplicity of regular file managers, but some times I would like to work faster/better with them.
If you compare IE 4 with IE 8 you can tell the advance ( even better compare IE 4 with Google Chrome )
But if you compare Windows 95 Explorer with Win XP they are almost the same!! ( Win Vista/7 is a step forward )
But I wonder: Why haven't file managers improved as much as webbrowsers?
That's one reason I like stuff like QuickSilver but it is just a step. Much work is needed to create something like a "Perfect program launcher" or (FileManager/DesktopSearcher etc as you wish )
QuickSilver featuring "move to" action
We are designing the UI for a new line of business application. We have no real constraints and are free to design the UI as we see fit. The UI will be done in WPF and targeted for Windows 7, Vista, and XP Pro users.
Many dialog boxes contain OK and Cancel buttons in their lower right corner. Do you feel it is necessary to have this Cancel button or is the red X in the upper right corner sufficient? We are discussing this as we have been noticing more UIs that do not have cancel buttons, only the red X.
Not only you should add it but also make sure ESC is mapped to it.
Present the two designs to the customer - one with the "Cancel" button, the other without. See what their thoughts are.
Better still present them as partially working prototypes and watch them as they use the dialogs. If you ask them to perform a set of tasks and see if they have trouble when asked to cancel an operation.
Having said that, my preference is to include a "Cancel" button for the reasons others have mentioned:
Accessibility (especially as Esc should be mapped to it).
Convention (users will be expecting it).
Include the Cancel button. The red X is VERY hard to tab to. ;)
Include it. This is very common in other user interfaces. Give the user the choice of which to use; making it for them might make them annoyed with your interface.
Users are used to having standard GUI layouts - otherwise they get confused. They also have different ways of using the standard interface. Some people only use the X, some people only use Cancel. People usually ignore the one they're not using, but get confused if their one isn't present. So be safe and keep them both in - it should only be a one-liner function for Cancek anyway.
Include it!
From a user interface perspective, not including a cancel button might leave some users feeling like they have no choice, which is certainly not the case. Imagine the following simple decision scenario:
Warning: All of the files in the selected folder will be deleted. This action cannot be undone. Are you sure you would like to continue?
How silly would an interface be if the only option was Ok? Also, as noted above, on many platforms the Escape key is mapped to Cancel. It's also probably worthwhile setting a default button so that pressing the Enter/Space key doesn't inadvertently perform the action that cannot be undone.
+1 on including it. If you don't include it now and then need some different functionality on Cancel to Close later on, your users will already be used to automatically closing.
Just like we have 'ESC' button on keyboard, we need 'Cancel' in dialogs.
A matter of usability :-)
Include it. And please also make sure that you make sure that hitting the Escape key does the same thing as the Cancel button.
Also, just because you're designing from scratch, please don't throw out all convention. Take a look at MSFT's UX Guidelines for dialog boxes.
The red button is really for 'Close' rather than 'Cancel'. 'Cancel' canceling a running task. Use a 'Close' button instead. And yes include the 'Close' if there is a reason for people to click on it. The red button is quite difficult to click when you really want to close something quickly.
If you have that kind of freedom, consider eliminating dialog boxes from your application entirely, especially ones with the typical "OK | CANCEL" paradigm. Dialog boxes disrupt the flow of action and generally should only be used for things which absolutely require the program to interrupt the user.
You'll notice how disruptive they are in the web environment -- e.g., Stack Overflow only uses them when it needs to be able to OVERRIDE your action, e.g., when you navigate away from an unsubmitted answer.
I'm currently working on a program that has many of those "the user SHOULD read it but he'll click OK like a stupid monkey" dialogs... So I was thinking of adding something like a captcha in order to avoid click-without thinking...
My ideas were:
Randomly change buttons
Randomly position buttons somewhere on the form
The user must click on a randomly colored word within the text he should read
add captcha
add captcha that includes the message for the user
Has anybody made any experience with such a situation. What would you suggest to do?
Well, you asked for opinions and here goes mine, but I don't think this is what you would like to hear...
Users like programs that they can depend on. They don't like when things change and they don't like to do extra work.
Randomly change buttons and Randomly position buttons somewhere on the form will only make them either press the wrong button or become annoyed with your application, because as you say, they don't read the text, and if you think about it, neither do we. As an example think of an Ok/Cancel dialog, you allways expect the ok button to be on the left, and most times i press it without reading it. It Will happen exactly the same with your users.
The user must click on a randomly colored word within the text he should read
add captcha
add captcha that includes the message for the user
With these 3 option you will add extra work to your application, your users will curse you for that. Just think of something that you would have to do 10x per day, let's say check in your code to source safe. How would you feel if your boss told you that from now on you will have to fill a captcha for each file you try to check in?
I think it's our jobs to make the lives of the people that use our software easier. If they must read some kind of text and they don't want to, there is absolutely no way you can make them do it.
You can´t make people work right, all you can do is provide them with the best possible tools and hope that they are professional enough to do their jobs.
So basically all i'm saying is, do your best to ease their work. If this is really important than you(or whoever is in charge) should talk to them and EXPLAIN WHY this is important.
You would be surprised on how people commit to things they understand.
I suggest that you don't; and that, unless you know better, you emulate respectable well-known, well-tested UIs like <big online retailer's> or <online banking site>.
Playing games with the user in order to get them to read messages is doomed. Users will focus mental resources on completing your game, rather than understanding the message. Your users may be less likely to actually understand the important part of the message if you have things like moved buttons, relabeling, scavenger hunts, captchas, or delays. They’ll focus on the instructions for the game, not on the real issue. Errors are likely to increase.
Users’ refusal to read message boxes is due to users wanting to get things done quickly rather than take the time to read stuff, and it is also due to message boxes being overused and misused so badly in so many apps. Including silly games in message boxes will just make users resent them all the more, compounding the problem.
Here’s what you can do:
Rule 1. Don’t use messages boxes. They should only appear for exceptional circumstances. An app should not have “many” message boxes. It should not be necessary to read a whole lot of documentation each time the user uses an app. If normal use of your app results in a message box, then your UI is wrong. Find another way.
Instead of verification messages, show clearly in the main window what has happened and provide a clear way to Undo it.
Use auto-correction, pictured/masked fields, and disabling rather than error messages.
Use good defaults and automation to avoid messages. For example, rather than showing an error message saying the user can’t upload because they’re not connected to the server, simply reconnect automatically.
Break commands along options. Rather that a message box to ask if the user wants paste with or without format, provide two different commands in the menu.
Don’t have information messages spontaneously popping up telling the user everything worked fine (e.g., “Preferences Saved!”)
Don’t have pop-ups providing helpful hints or documentation. Provide a tutorial or balloon help if you can’t make your UI self-documenting.
Don’t have nagging “upgrade me” messages.
Consider providing message text in the main window rather than in a separate message box (e.g., “Page may not look or act right because ActiveX is off for security.”). Pop-ups from web surfing have conditioned users to automatically dismiss anything that pops up as irrelevant.
Rule 2. If you have to use a message:
Make the text as brief as possible to get the key information across. More text is not equivalent to more helpful. Use “No match to [filemask] in [path].” Don’t use “Nonfatal Error 307: Search action aborted. [Appname] is unable to complete your string search for the regular expression you provided because the file mask you gave, namely [filemask], does not result in any matching files in the directory that you specified (which was [path]). Please check your filemask or path selection and again re-enter it or them in the Files to Search dialog box. Click the OK button below on this message box to return to the Files to Search dialog box. Click the Cancel Button on the Files to Search dialog when you get there to cancel your search for strings.” If there are some users who will need more explanation than can be achieved in a brief message, provide a Help button or a “How do I…” link in the message box.
Use plain language and no jargon in the message. That includes “innocent” words like “dialog,” “database,” and “toner.” Do not take raw exception text and throw it in a error message. Do not include any error numbers or dumps; log these instead. Purge your app of any debugging message boxes left by developers. Better to simply let the app disappear on a fatal error than to put up a message full of jargon and then the app disappears.
Label the buttons of a message box with what the action does, not “OK.” At the very least, the users have to focus on the activating button to dismiss a message box. If that button is labeled something like “Delete” or “Install,” it should give them pause. You should never have to explain in your message text what each button does. BTW, such labeling is a GUI standard on most platforms.
Redesign your application so that it does not use message boxes.
My suggestion, live with it or redesign your dialogs/interface. Do not add randomness to dialogs or otherwise treat the user like an idiot, even though you may think most are :-).
I just recently read a Joel on Software article, Designing for People Who Have Better Things To Do With Their Lives. It makes the point that most people won't read anything and discusses ways to work around that or at least not make it worse.
You could try with a timer which waits for the "supposed reading time" before enabling the submit button. You can even calculate the supposed reading time from the number of words.
I think that subtle ways to force the user to read your text (like moving around buttons or asking them to read a captcha) can make them feel like stupid monkeys.
You could use a choice question based on what the user should read.
This is inspired by the question OK-Cancel or Cancel-OK?.
I remember reading somewhere about the concept of switching OK-Cancel/Cancel-OK in certain situations to prevent the user from clicking through information popups or dialog boxes without reading their content. As far as I remember, this also included moving the location of the OK button (horizontally, left to right) to prevent the user from just remembering where to click.
Does this really make sense? Is this a good way to force the user to "think/read first, then click"? Are there any other concepts applicable to this kind of situation?
I am particularly thinking of a safety-related application, where thoughtlessly pressing OK out of habit can result in a potentially dangerous situation whereas Cancel would lead to a safe state.
Please don't do this unless you are really, really, really sure it's absolutely required. This is a case of trying to fix carelessness and stupidity by technological means, and that sort of thing almost never works.
What you could do is use verbs or nouns instead of the typical Windows OK / Cancel button captions. That will give you an instant attention benefit without sacrificing predictability.
NOOOOOOOOOOOO!
In one of our products we have a user option to require Ctrl+Click for safety related commands.
But startling the user with buttons that swap place or move around is bad design in my book.
NO. If you make it harder for the user to click OK by mistake and force them to think, they will still only think harder about how to click OK -- they will not think about the actual thing they're trying to carry out. See usability expert Aza Raskin's article: Never use a warning when you mean Undo. Quote:
What about making the warning
impossible to ignore? If it’s
habituation on the human side that is
causing the problem, why not design
the interface such that we cannot form
a habit. That way we’ll always be
forced to stop and think before
answering the question, so we’ll
always choose the answer we mean.
That’ll solve the problem, right?
This type of thinking is not new: It’s
the
type-the-nth-word-of-this-sentence-to-continue approach. In the game Guild Wars, for
example, deleting a character requires
first clicking a “delete” button and
then typing the name of the character
as confirmation. Unfortunately, it
doesn’t always work. In particular:
It causes us to concentrate on the unhabitual-task at hand and not on
whether we want to be throwing away
our work. Thus, the
impossible-to-ignore warning is little
better than a normal warning: We end
up losing our work either way. This
(losing our work) is the worst
software sin possible.
It is remarkably annoying, and because it always requires our
attention, it necessarily distracts us
from our work (which is the second
worst software sin).
It is always slower and more work-intensive than a standard
warning. Thus, it commits the third
worst sin—requiring more work from us
than is necessary.
[If you want a Microsoftish one, this one by a .NET guy on MSDN says the same thing!]
If you must use a dialog, put descriptive captions on the buttons within the dialog.
For example, instead of OK and Cancel buttons, have them say "Send Invoice" and "Go Back", or whatever is appropriate in the context of your dialog.
That way, the text is right under their cursor and they have a good chance of understanding.
The Apple Human Interface Guideline site is a great reference, and very readable. This page on that site talks about Dialogs.
Here is an example image:
(source: apple.com)
No, it doesn't make sense. You're not going to "make" users read. If the decision is that crucial, then you're better off finding a way to mitigate the danger rather than handing a presumed-careless user a loaded gun.
Making the "safe" button default (triggered by enter/spacebar/etc.) is a good idea regardless, simply because if they surprise the user then a keystroke intended for the expected window won't accidentally trigger the unexpected action. But even in that scenario, you must be aware that by the time the user has realized what they've done, the choice is already gone (along with any explanatory text on the dialog). Again, you're better off finding another way to give them information.
What I've done in some instances was to compare the time of the message box being shown with the time of it being dismissed. If it was less than 'x' amount of seconds, it popped right back up. This forced them, in most cases, to actual read what was on the screen rather than just clicking through it blindly.
Fairly easy to do, as well....
Something like this:
Dim strStart As DateTime = Now
While Now < strStart.AddSeconds(5)
MessageBox.Show("Something just happened", "Pay Attention", MessageBoxButtons.OK)
If Now < strStart.AddSeconds(5) Then strStart = Now Else Exit While
End While
At the end of the day you can't force a user to do something they're unwilling to do... they will always find a way around it
Short cut keys to bypass the requirement to move the mouse to a moving button.
Scrolling down to the bottom of the EULA without reading it to enable to continue.
Starting the software and then going to get their cup of tea while waiting for the nag screen to enable the OK button.
The most reliable way I've seen this done is to give a multiple choice question based on what is written. If they don't get the answer correct, they can't continue... of course after a couple of times, they'll realise that they can just choose each of the answers in turn until the button enables and then click it. Once again meaning they don't read what was written.
You can only go so far before you have to put the responsibility on the user for their actions. Telling the user that their actions are logged will make them more careful - if they're being held accountable, they're more likely to do things right. Especially if there's a carefully crafted message that says something like:
This is being logged and you will be held accountable for any
repercussions of this decision. You have instructed me to delete
the table ALL_CORPORATE_DATA. Doing so will cause the entire company's
database to stop working, thus grinding the whole company to a halt.
You must select the checkbox to state that you accept this responsibility
before you can choose to continue...
And then a checkbox with "Yes, I accept the responsibility for my actions" and two buttons:
"YES, I WANT TO DELETE IT" this button should only be enabled if the checkbox is checked.
"OH CRAP, THAT'S NOT WHAT I MEANT AT ALL" this button can always be enabled.
If they delete the table and the company grids to a halt, they get fired. Then the backup is restored and everyone's happy as Larry [whoever Larry is] again.
Do NOT do it, please. This will have no positive effect: You are trying to AVOID people's clicking OK instead of Cancel, by making them potentially click Cancel instead of OK (okay, they may try again). But! you might as well achieve people's clicking OK when they really want to cancel and that could be a real disaster. It's just no good.
Why not reformulate the UI to make the OK the "safe choice"?
The problem is better solved with a combination of good feedback, communication of a system model and built-in tolerance.
In favor of the confirmation mechanism speaks the simplicity of implementation. From programmer's point of view it's the easiest way of shifting responsibility onto user: "Hey, I've asked you if you really want to shoot yourself into the foot, haven't I? Now there is no one to blame but yourself..."
From user point of view:
There is a productivity penalty of having to confirm operation twice every time even though actual mistakes take up just a fraction of total number of actions, any switching of buttons, breaking the habitual workflow or inserting a pause into confirmation just increases the penalty.
The mechanism doesn't really provide much safety net for frequent users whose reflexes work ahead of the concious mind. Personally I have many times done a complex sequence of actions only to realise a moment later when observing the consequences that my brain somehow took the wrong route!
A better for the user, but more complex (from software development point of view) solution would be:
Where possible communicate in advance what exact affect the action is going to make on the system (for instance Stack Overflow shows message preview above Post Your Answer button).
Give an immediate feedback to confirm once the action took place (SO highlights the freshly submitted answer, gmail displayes a confirmation when a message is sent etc).
Allow to undo or correct possible mistake (i.e. in SO case delete or edit the answer, Windows lets restore a file from recycle bin etc). For certain non-reversible actions it's still possible to give an undo capability but for a limited timeframe only (i.e. letting to cancel or change an online order during the first 10 minutes after its submission, or letting to recall an e-mail during the first 60 seconds after its been "sent", but actually queued in the outbox etc).
Sure, this is much more initial work than inserting a confimation message box, but instead of shifting the responsibility it attempts to solve the problem.
But if the OK/Cancels are not consistent, that might throw off or upset the user.
And don't do like some EULAs where a user is forced to scroll a panel to the bottom before the Agree button becomes clickable. Sometimes you just won't be able to get a user to read everything carefully.
If they really need to read it, maybe a short delay should happen before the buttons appear? This could also potentially be annoying to the user, but if it is a very critical question, it'd be worth it.
Edit: Or require some sort of additional mechanism than just clicking to "accept" the very important decision. A check box, key press, password, etc.
I recommend informing the user that this is a critical operation by using red text and explaining why is this an unsafe operation.
Also, rather than two buttons, have two radio buttons and one "Ok" button, with the "don't continue" radio button selected as default.
This will present the user with an uncommon interface, increasing cognitive load and slowing him down. Which is what you want here.
As always with anything with user interaction, you have a small space between helping the user and being annoying. I don't know you exact requirements but your idea seems OK(pun intended) to me.
It sounds like your user is going through a type of input wizard in the safety app.
Some ideas as alternatives to moving buttons.
Have a final screen to review all input before pressing the final ok.
Have a confirmation box after they hit ok explaining what the result of this action will be.
A disclaimer that require you to agree to it by checking a box before the user could continue.
Don't switch it around - you'll only confuse more than you'll help.
Instead, do like FireFox and not activate the control for 5 sec. - just make sure you include a timer or some sort of indicator that you're giving them a chance to read it over. If they click on it, it cuts off the timer, but requires they click one more time.
Don't know how much better it will be, but it could help.
Just remember, as the man said: You can't fix stupid.
This will give me headache. Especially when I accidentally close the application and forget to save my file :(
I see another good example of forcing user to "read" before click: Firefox always grayed out the button (a.k.a disable) the "OK" button. Therefore the user have to wait around 5 seconds before he can proceed to do anything. I think this is the best effort I have seen in forcing user to read (and think)
Another example I have seen is in "License and Agreements" page of the installer. Some of them required the user to scroll down to the end of the page before he/she can proceed to next step.
Keyboard shortcuts would still behave as before (and you'd be surprised how few people actually use mice (especially in LOB applications).
Vista (and OSX IIRC) have moved towards the idea of using specific verbs for each question (like the "Send"/"Don't send" when an app wants to crash and wants to submit a crashdump to MS)
In my opinion, I like the approach used by Outlook when an app tries to send an email via COM, with a timer before the buttons are allowed to be used (also affects keyboard shortcuts)
If you use Ok and Cancel as your interface you will always be allow the user to just skip your message or screen. If you then rearrange the Ok and Cancel you will just annoy your user.
A solution to this, if your goal is to insure the users understanding, is:
Question the user about the content. If you click Ok you are agreeing to Option 1, or if you click Ok you are agreeing to option 2. If they choose the correct answer, allow the action.
This will annoy the user, so if you can keep track of users, only do it to them once per message.
This is what I responded to Submit/Reset button order question and I think the same principle can be used here. The order does not really matter as far as you make sure the user can distinguish the two buttons. In the past what I have done is used a button for (submit/OK) button and used a link for (reset/cancel) button. The users can instantly tell that these two items are functionally different and hence treat them that way.
I am not really for OK/Cancel. It's overused and requires you to read the babbling in order to say what you are OKing or Canceling. Follow the idea of MacOSX UI: the button contains a simple, easy phrase that is meaningful by itself. Exampleç you change a file extension and a dialog pops up saying:
"Are you sure you want to change the extension from .py to .ps?"
If you perform the change, the document could be opened by a different application.
(Use .ps) (Keep .py)
It is way more communicative than OK/Cancel, and your question becomes almost superfluous, that is, you just need to keep active the rightmost button, which seems to be the standard.
As it concerns the raw question you posed. Never do it. Ever. Not even at gunpoint. Consistency is an important requisite for GUIs. If you are not consistent you will ruin the user experience, and your users will most likely to see this as a bug than a feature (indeed it would be a BUG). Consistency is very important. To break it, you must have very good reason, and there must not be another different, standard way to achieve the same effect.
I wonder if you're thinking about the option that exists in Visual Basic where you can set various prompts and response options; and one option is to allow you to switch Cancel and OK based on which should be the default; so the user could just hit enter and most of the time get the proper action.
If you really want to head in this direction (which I think is a bad idea, and I'm sure you will too after little reflection and reading all the oher posts) it would work even better to include a capcha display for OK.