Regresssion: Composition drawing broken in multi-window app (worked in 1.5)

[DHancock]

Describe the bug

The PointerOver test on controls fails intermittently in the first window after a second window is opened when built with WinAppSdk 1.6. The bug isn't evident 100% of the time, but in my set up it's > 50%. I haven't been able to reproduce this behaviour building against WinAppSdk 1.5.

Please see the video of the attached project running. You can see as the mouse is moved over the button on the first window, the PointerOver indication flashes then goes out, although the button isn't clicked (I changed the PointerOver brush to make it more obvious). You can still click on the button successfully even when the pointer over isn't shown.

Other controls exhibit the same fault. Trimming (or not) doesn't change the out come. Removing the mica background did make it more difficult to reproduce, but it may be a simple timing issue. I'm not sure if this is win app sdk or xaml bug.

trimmed.mp4

Steps to reproduce the bug

• Build and run the attached project
• Click the "New Window..." button
• Switch back to the first window
• Move the mouse over the button to see the effect

MouseOverWeirdness.zip

Expected behavior

No response

Screenshots

No response

NuGet package version

WinUI 3 - Windows App SDK 1.6.1: 1.6.240923002

Windows version

Windows 11 (22H2): Build 22621

Additional context

No response

[DHancock]

Edit: Of course it's pointer over not mouse over. I've also made the repro project code a bit more robust, but didn't change it functionality.

The fault is easier to reproduce in my actual app, which has a more complex ui. Build the master branch if required. The video again demonstrates the fault. The colour picker palette entries animate using a scale transition that's triggered by a pointer entered event handler. That now fails as does hovering over the tab item header.

app.mp4

[DHancock]

Windows App Sdk 1.6.2 has been released with this bug still reproducable