Reset MouseIsOver when the control loses focus

[LeafShi1]

Fixes #12590

Proposed changes

• Set MouseIsOver = false in OnLostFocus method of ComboBox.cs

Customer Impact

• ComboBox dropdown button can be shown normally when switching RightToLeft property, or recreating the combobox for any other reason.

Regression?

• Yes

Risk

• Minimal

Screenshots

Before

When change the RightToLeft property after expanding the Popup FlatStyle comboBox, the dropdown button on the comboBox disappeared

After

The dropdown button on the comboBox can be show normally

Test methodology

• Manually

Test environment(s)

• .net 10.0.0-alpha.1.24605.1

Microsoft Reviewers: Open in CodeFlow

[codecov]

Codecov Report

Attention: Patch coverage is 96.87500% with 1 line in your changes missing coverage. Please review.

Project coverage is 76.01419%. Comparing base (af49f16) to head (9aa73b0).
Report is 87 commits behind head on main.

Additional details and impacted files

@@                 Coverage Diff                 @@
##                main      #12598         +/-   ##
===================================================
+ Coverage   75.73242%   76.01419%   +0.28176%     
===================================================
  Files           3153        3175         +22     
  Lines         635807      638857       +3050     
  Branches       46975       47178        +203     
===================================================
+ Hits          481512      485622       +4110     
+ Misses        150870      149737       -1133     
- Partials        3425        3498         +73     

Flag	Coverage Δ
Debug	76.01419% <96.87500%> (+0.28176%)	⬆️
integration	18.13703% <50.00000%> (-0.11750%)	⬇️
production	49.79246% <83.33333%> (+0.48693%)	⬆️
test	97.03785% <100.00000%> (-0.01208%)	⬇️
unit	46.99174% <83.33333%> (+0.72867%)	⬆️

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[ricardobossan]

I proceeded to test this PR and the issue has been resolved:

All LGTM!