Fix cursor editor icon width calculation for proper DPI scaling

[Copilot]

Fixes #14167

Root Cause

Icons similar to HSplit.cur, VSplit.cur are wider than other icons at certain DPI settings (such as 125%, 175%， 225%， 250%), which is causing the webtable to display abnormally.

Proposed changes

• Modify the drawing method for list items to use the default icon width as a reference, ensuring that all icons are the same size.

Customer Impact

• Cursor editor items are displayed correctly in propertyGrid with all DPI settings.

Regression?

• No

Risk

• Minimal

Screenshots

Before

After

150DPI:

150DPI.mp4

175DPI:

175DPI.mp4

200DPI:

200DPI.mp4

225DPI:

225DPI.mp4

Test methodology

• Manually

Test environment(s)

• 11.0.0-alpha.1.25619.109

Microsoft Reviewers: Open in CodeFlow

[codecov]

Codecov Report

❌ Patch coverage is 42.85714% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 77.15187%. Comparing base (05b7c2e) to head (580788c).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@                 Coverage Diff                 @@
##                main      #14168         +/-   ##
===================================================
- Coverage   77.15877%   77.15187%   -0.00691%     
===================================================
  Files           3279        3279                 
  Lines         645333      645335          +2     
  Branches       47720       47720                 
===================================================
- Hits          497931      497888         -43     
- Misses        143719      143749         +30     
- Partials        3683        3698         +15     

Flag	Coverage Δ
Debug	77.15187% <42.85714%> (-0.00691%)	⬇️
integration	18.97192% <0.00000%> (-0.03218%)	⬇️
production	52.01441% <42.85714%> (-0.01530%)	⬇️
test	97.40559% <ø> (ø)
unit	49.45494% <42.85714%> (+0.01250%)	⬆️

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[SimonZhao888]

Here is another issue: when the DPI is set to 125%, 175%, 225%, 250%, the .cur icon exhibits an icon offset problem.
Normal：

Offset：

[Copilot]

Pull request overview

This PR fixes a DPI scaling issue in the cursor editor where certain cursors (HSplit, VSplit) appeared wider than others at specific DPI settings (125%, 175%, 225%, 250%), causing display alignment issues in the PropertyGrid. The fix standardizes icon width by calculating it once using the default cursor as a reference, rather than computing individual widths for each cursor during drawing.

Key changes:

• Introduces a _cursorWidth field calculated once in the constructor using Cursors.Default
• Refactors OnDrawItem to use the pre-calculated width instead of computing it per cursor
• Improves performance by eliminating repeated DPI scaling calculations during drawing