Do add-in commands in Outlook supersede custom panes? - outlook

Question

If I add the VersionOverrides element to define a custom Ribbon button to launch a task pane for my add-in, the tab for my custom pane is no longer visible in Outlook 2016, but it is in Outlook Online/OWA. It is defined without any activation rules so it should appear for every read message. So is it a bug or by design that the tab is hidden if I've defined a custom Ribbon button to launch it? If I remove the VersionOverrides element the tab appears again.

Answer 1

Edit Nov 2016. For Outlook add-ins custom panes are considered absolete
https://dev.office.com/blogs/make-your-add-ins-available-in-the-office-ribbon
Old answer:
I have discussed similar topic with a Senior Product Manager of Office extensibility. I hope he would not mind if I quote him. Outlook web add-ins Custom panes should be considered:
just legacy support for clients which don't today support Office commands. Commands provide a much more intuitive, natural and engaging way to use add-ins, which is why we’re pushing for them very hard.
Having said that, OWA does not support commands yet. Owa looks in your manifest for the old FormSettings element and display your custom pane same as before when add-ins commands did not exist. Same thing for Office 2016 when there is no VersionOverrides element in your manifest for retro-compatibility purposes.
Now it is difficult for us, add-ins developers, to propose now an add-in with completely different UX between OWA and Desktop. Then, if you want to have the Custom Pane working with Add-ins commands in Outlook Desktop 2016 (only host that supports commands at the time of the writing) you have to specified it with an ExtensionPoint with type xsi:type="CustomPane" in your VersionOverrides see this example
<VersionOverrides xmlns="http://schemas.microsoft.com/office/mailappversionoverrides" xsi:type="VersionOverridesV1_0">
<Requirements>
<bt:Sets DefaultMinVersion="1.3">
<bt:Set Name="Mailbox" />
</bt:Sets>
</Requirements>
<Hosts>
<Host xsi:type="MailHost">
<DesktopFormFactor>
<FunctionFile resid="functionFile" />
<ExtensionPoint xsi:type="CustomPane">
<RequestedHeight>250</RequestedHeight>
<SourceLocation resid="customPaneUrl"/>
<Rule xsi:type="RuleCollection" Mode="Or">
<Rule xsi:type="ItemIs" ItemType="Message"/>
</Rule>
</ExtensionPoint>
<ExtensionPoint xsi:type="MessageReadCommandSurface">
<OfficeTab id="TabDefault">
<Group id="msgReadDemoGroup">
<Label resid="groupLabel" />
<Tooltip resid="groupTooltip" />
<Control xsi:type="Button" id="msgReadOpenPaneButton">
<Label resid="paneReadButtonLabel" />
<Tooltip resid="paneReadButtonTooltip" />
<Supertip>
<Title resid="paneReadSuperTipTitle" />
<Description resid="paneReadSuperTipDescription" />
</Supertip>
<Icon>
<bt:Image size="80" resid="test-icon-80" />
</Icon>
<Action xsi:type="ShowTaskpane">
<SourceLocation resid="taskPaneUrl" />
</Action>
</Control>
</Group>
</OfficeTab>
</ExtensionPoint>
</DesktopFormFactor>
</Host>
</Hosts>
<Resources>
</Resources>
</VersionOverrides>