winforms MonthCalendar accessible objects are leaking in memory

.NET version

8.0.100-alpha.1.22430.2

Did it work in .NET Framework?

No

Did it work in any of the earlier releases of .NET Core or .NET 5+?

No

Issue description

MonthCalendar accessible objects are left in memory after the MonthCalendar control instance was inspected with accessibility tool: just Narrator and the form with MonthCalendar is closed, garbage is collected, but Narrator is still opened.

Report from WinDbg:

Steps to reproduce

Create a parent form with two buttons: one will be opening a child form with the MonthCalendar control and the other will collect the garbage.
Press the second button to open the child form with MonthCalendar.
Start the Accessibility Insights tools.
Run automated checks for the MonthCalendar control using Narrator.
Close the child form.
Clear memory with the first button of the parent form.
DON'T close Narrator.
Look for MonthCalendar accessible objects left in memory (using WinDbg, or dotMemory, or another suitable tool).

Tested sample application: WinFormsApp5_MonthCalendar.zip

Sep 01 '22 10:09 Olina-Zhang

@vladimir-krestov / @dmitrii-drobotov can you assign this to the appropriate person on your team? Not an urgent issue but one good to fix as much as possible.

Sep 07 '22 00:09 merriemcgaw

Re-tested this issue on Win10 and Win11 as following steps, found it just repro on Win10.

Repro steps:

Launch test project in .Net 8.0
Launch Windbg and attach this test app
Open Narrator, and click Go button in Windbg
Focus on test app, click OpenMonthCalendar button to open another form with MonthCalendar
Focus on MonthCalendar, click some specific dates, then click Previous, Next buttons more times
Click year button, then click today button, click date to specific day
Click Previous Button
Close Form with monthCalendar
Click GC.Collect button more times to 0
In Windbg to input following to check if there has some AO memory leak: