fix #12916 Cannot use down to expand ToolStripDropDownButton in toolStrip2 after using right/Left to collapse ToolStripDropDownButton in toolStrip1

[Epica3055]

Fixes #12916

Root cause

When we use Tab key to focus on second ToolStrip and then press down key, ProcessCmdKey method get triggered, but the event owner isn't right, it should have been toolStrip2 not toolStrip1.

Proposed changes

• Set Active ToolStrip when ToolStrip get focused.

Screenshots

Before

After

Test methodology

• manually

Microsoft Reviewers: Open in CodeFlow

Copilot reviewed 1 out of 1 changed files in this pull request and generated no comments.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.09527%. Comparing base (ff19802) to head (ef980e9).
Report is 108 commits behind head on main.

Additional details and impacted files

@@                 Coverage Diff                 @@
##                main      #13034         +/-   ##
===================================================
- Coverage   76.13911%   76.09527%   -0.04385%     
===================================================
  Files           3258        3272         +14     
  Lines         642851      643701        +850     
  Branches       47307       47438        +131     
===================================================
+ Hits          489461      489826        +365     
- Misses        149825      150314        +489     
+ Partials        3565        3561          -4     

Flag	Coverage Δ
Debug	76.09527% <100.00000%> (-0.04385%)	⬇️
integration	18.04832% <100.00000%> (-0.12485%)	⬇️
production	50.11025% <100.00000%> (+0.02727%)	⬆️
test	96.95227% <ø> (-0.01762%)	⬇️
unit	47.54096% <100.00000%> (+0.11339%)	⬆️

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[ricardobossan]

All LGTM!