Description

In a .NET MAUI application on the Windows platform, adding new items to a CollectionView using the "Add New Item" button does not reflect in the UI, although the underlying data count increases. Similarly, clicking the "Add New Group" button causes the app to freeze temporarily before closing the window unexpectedly.
This issue occurs exclusively on the Windows platform and does not affect other platforms.

Note: While fixing this issue enable the following UITest in HostApp: Issue17969

In windows,

In mac,

Steps to Reproduce

1. Launch the .NET MAUI application on the Windows platform. CollectionViewAddItem.zip

2. Observe the initial grouped list of animals displayed in the CollectionView.

3. To reproduce the "Add New Item" issue:

   • Click the "Add New Item" button.
   • Note that no new items appear in the CollectionView, but the underlying Animals collection has its count increased.

4. To reproduce the "Add New Group" issue:

   • Click the "Add New Group" button.
   • Observe that the application enters a loading state, freezes momentarily, and then crashes or closes the window unexpectedly.

Expected Behavior:

• Clicking "Add New Item" should immediately display the new item in the CollectionView.
• Clicking "Add New Group" should add a new group to the CollectionView and update the UI without freezing or crashing.

Actual Behavior:

• Clicking "Add New Item" updates the data source but does not display the new item in the CollectionView.
• Clicking "Add New Group" results in a loading state, then crashes or closes the window.

Link to public reproduction project repository

No response

Version with bug

9.0.30 SR3

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

Unknown/Other

Affected platforms

Windows

Affected platform versions

No response

Did you find any workaround?

No response

Relevant log output