Either this is just a deprecated window style with no documentation, or I've made a flaw in searching for it.
My question is, what does this flag do? Is there a supported equivalent to it that I may need?
Advice is appreciated!
WS_EX_APPWINDOW is an extended window style that is documented on MSDN. It is most definitely not deprecated and is a fully supported and widely used style.
The documentation states that the style:
Forces a top-level window onto the taskbar when the window is visible.
This is a relatively bland statement that undersells the purpose of this style. Normally the property that forces a top-level window onto the taskbar is the fact that the top-level window is unowned. Top-level owned windows do not, by default, appear on the taskbar. So, if for some reason you wish to put a top-level owned window onto the taskbar, then WS_EX_APPWINDOW is the solution.
Although there is an MSDN article that describes the rules for which windows appear in the taskbar, it is not as clear as it should be. Raymond Chen's article describes it much more precisely:
There are some basic rules on which windows go into the taskbar. In
short:
If the WS_EX_APPWINDOW extended style is set, then it will show (when visible).
If the window is a top-level unowned window, then it will show (when visible).
Otherwise it doesn't show.
According to Extended Window Styles on MSDN it:
Forces a top-level window onto the taskbar when the window is visible.
I don't see anywhere on the CreateWindowEx documentation that marks it as no longer supported.
Related
When a focused window is closed, Windows will typically set focus to a different window when possible. I'm trying to figure out what exactly causes this to happen, and in what scenarios does this not occur.
I'm noticing that when some windows are closed, they do not cause the OS to set focus to a new window (eg. Discord, Slack). Discord and Slack are both hidden instead of destroyed on close, but then there are also other windows that when hidden will still cause the OS to set focus to a different window. One such example is with a fresh WPF app and changing the window's Visibility to Collapsed - this causes the window to be hidden, not destroyed, and yet the OS reassigns focus to another window.
What causes some windows when hidden to reassign focus (eg. WPF collapse)? As opposed to applications like Discord/Slack, which are hidden, yet do not reassign OS focus.
It's a multi-step dance of message exchanges, and I no longer have all the details cached in my head. So, generally speaking ...
There's a distinction between activating a window and setting the focus to a window. Windows can get activated in various ways, including a mouse click (either in the client or non-client areas, a keyboard operation, a window being created by a process that currently has "the foreground love", etc.)
A window that's activated can (in effect) accept the focus, reject the focus, or direct the focus to another window (such as a child window like an edit control or button).
A window that doesn't make the effort to direct the focus explicitly when its activated will (likely) end up with the focus by default. That's mostly an artifact of how DefWindowProc handles the relevant messages. But if it's using the dialog manager, then the dialog manager will (if I recall correctly) set the focus to one of the child windows that has the WS_TABSTOP window style.
Imagine a simple text editor application that has a top-level window and one child window that fill the top-level window's client area and hosts the actual editor functionality. In normal behavior, the child window would have the focus whenever the application is in the foreground. But if the top-level window is activated (for something other than a mouse click in the child window's client area), and the top-level window fails to redirect the focus to its child, then it may appear as though nothing has the focus because the window that does have the focus doesn't respond to most kinds of keyboard input.
Key messages involved include: WM_ACTIVATEAPP, WM_NCACTIVATE, WM_ACTIVATE, WM_MOUSEACTIVATE, WM_SETFOCUS, and WM_KILLFOCUS.
Edited to emphasize
what causes the OS to re-assign focus from a window?
In most cases, the OS does not assign focus. It activates and deactivates windows, and the affected applications respond to those events by setting the focus. Applications have a lot of flexibility in how to respond. So if there's an anomaly in where the focus is, it may be more of a question about the behavior of individual applications than about Windows.
It's also possible for a window to have focus but for it to seem as if no window has focus. One case is where the top-level window has focus but doesn't react to the keyboard itself because focus is normally supposed to be assigned to one if its child windows. It's also possible for a hidden window (at least a hidden child window) to have focus if it's not disabled.
Win32's DefWindowProc and dialog-specific APIs, MFC, WPF, and other frameworks generally provide "standard" behavior for handling focus and activation in common cases. But there's a lot of nuance, and there are inherently some differences. For example, WPF applications (if I recall correctly) use windowless child controls, so the traditional behaviors have to be implemented by the framework.
So, I have a dialog based application using pure WinAPI. There is a main dialog, and then multiple other dialogs that are toolwindows. These toolwindows are meant to free-float around, the user can drag them, hide them, and show them, but they have no taskbar entry. This is what I intended, but the problem is, when I switch from the main window to a different application, then click on the taskbar entry for the main window, the main window will show up, but the toolwindows will not. They stay hidden behind the main window and sometimes windows of other applications, and you cannot use them until you move all of the top-most windows and hunt down the toolwindow.
So, what I'm trying to do to work around this is, when the user restores the window from being minimized, I want to enumerate through all of the tool windows and bring them to the front, maybe by calling SetActiveWindow().
But what message gets sent when the window is restored? I was thinking WM_SHOW, or WM_RESTORE, but they don't exist.
Another question, and if you answer this the first question is irrelevant because I will no longer need to use that workaround: Is there a better method of bringing all tool-windows to the front?
Give the tool windows the WS_POPUP style (and not WS_OVERLAPPED), and make the main window their parent (strictly it is their owner window). That way the tool windows will remain on top of the main window. This may (or may not) be what you want.
The naive answer to the question is to listen to WM_SIZE and respond to a wParam value of SIZE_RESTORED.
The other obvious possibility is to make all the tool windows be owned by the main window. So long as you are happy for the tool windows always to be on top of the main window, this will solve your problem. The owned windows will be hidden when the owner is minimized, and re-shown when the owner is restored.
Learn more about ownership in the MSDN topic on Window Features.
I would like to add my custom command, to a window system menu (the one usually on the left top on titlebar, usually containing Minimize, Maximize and so on), and respond to it in my application.
In ms windows one can do
HMENU hMenu = GetSystemMenu(hwnd, false);
AppendMenu(hMenu, MF_STRING, ...)
Is something like this possible under X11? If not a general method maybe a solution for some specific window manager?
Ok, after your last edit, what I understand is that you want to add your custom menu to the menu that's on the window decoration, which is controlled by the Window Manager.
I don't think that's possible, although I'm not sure. I believe you should read the ICCCM and the EWMH to find if this is possible or not:
http://en.wikipedia.org/wiki/Inter-Client_Communication_Conventions_Manual
http://en.wikipedia.org/wiki/Extended_Window_Manager_Hints
Or you can send an email to wm-spec-list asking:
http://mail.gnome.org/mailman/listinfo/wm-spec-list
Also, adding an option there makes it quite hidden, doesn't it? I guess most people don't ever click that menu... I don't even think that menu exists on all the possible Window Managers. You should really try to put your menu inside your application's Window instead of the Window Manager's decoration. Some environments don't even have Window Managers: what would your users do in this case?
Note that some applications (like the Chromium browser) don't use the Window Manager decorations: they implement their own decoration, they implement their own close/maximize/minimize buttons. This way, they have complete control over all the decoration buttons and menus, but their decoration doesn't have the same "look and feel" of the rest of the desktop. You could think about doing this, but I wouldn't encourage that... You should probably put your menu somewhere else (where it's not that hidden...).
You mean you want to add your app to the system menu?
I believe most modern desktop environments implement the XDG Menu Standard:
http://standards.freedesktop.org/menu-spec/menu-spec-latest.html
You'll have to learn other standards too probably:
http://standards.freedesktop.org/
They're all somehow short, so they won't consume more than some hours to read and learn.
I'm writing a Win32 plug-in DLL for a third-party MFC app. The DLL needs to display a modal dialog. When I do this using DialogBox() or other plain Win32 API (e.g. I tried to write my own modal loop), the main application's window doesn't redraw all elements: it redraws standard elements, but not the client area. Modeless dialogs display just fine.
I suspect this happens because MFC doesn't really have modal dialogs in Win32 sense. It can only have one message loop and a separate loop in DialogBox() disrupts its delicate machinery. Here's a CodeProject article that explains this. But this CodeProject article is 9 years old, so maybe things have changed since then. Could somebody shed some light on this? The app uses MFC 8 (i.e. mfc80.dll).
Update. Here's a link to the original question; it may contain some additional information.
Update 2. Thanks everyone; I really appreciate all the advice, it certainly helps me to get the big picture of how things fit together. The first path I'm going to explore is to use native MFC 'modal' dialogs. (Since I do all this from Python, I'll use Python bindings for MFC, pywin32). This will take some time; when it's ready, I'll update the post with results.
Every thread can have a message loop. Put your modal dialog into a separate thread and emulate the standard behavior of Windows by disabling the parent window.
Edit: after some discussion (see below) it appears that the parent code behaves incorrectly.
Still, I think there are possible workarounds. One could be a parent window (to the modal dialog, but child to the one that currently behaves incorrectly) that overlays the erroneous window content, but redraws it from a DC in memory to mimic correct behavior. Of course the parent window still would have to be disabled. Another solution may be to subclass the parent window, to correct the behavior. Since the plugin would run within the same process, the implementation should be straightforward.
This question is more academic than practical and doesn't involve any one specific language. For the sake of discussion, we'll use Win32 API.
What is the most appropriate way to create a window with the following behavior goals:
Z-Order is lower than every other window except the desktop surface.
Cannot be made to appear on a higher z-order than other windows through mouse or keyboard clicks.
Assumption may be made that the window is borderless.
There are two basic approaches here :-
make your window the 'child' of the desktop.
make your window simply refuse to accept focus or activation :-
The wonder of the windows window manager is that there isn't one. Rather, there is an appearance of a window manager as a result of the emergent behavior of all the windows in the system - namely how they react to messages - which in 99% of cases is handeld by DefWindowProc.
Which means that you can subvert a lot of normal window manager type behaviour by handling messages before DefWindowProc. If you create a window, and position it using the relevent flags at the bottom of the z-order with SetWindowPos, and then handle messages like WM_WINDOWPOSCHANGING, you can ensure that your window never receives activation or focus and always - even when other apps call SetWindowPos - always has the z-bottom flag set.
both approaches are problematic as its very difficult to find out what the desktop window is. GetDesktopWindow returns a handle to a window that is only ever visible if explorer crashes. The rest of the time, the visible desktop is a window created by explorer - ultimately a syslistview control. Spy++ + Findwindow will get you a handle to the window you want to be above.