[Bug]: Small square rendered next to Close button on KryptonForm when using a custom theme

[mcpbcs]

Summary

A small unexpected square appears next to the Close (X) button on the title bar of a KryptonForm when a custom palette/theme is applied.

Description

Observed behavior
When running a KryptonForm with a custom theme/palette, a small square is drawn next to the Close button in the title bar. This element does not appear when using built-in palettes such as Office2010 or Office365.
Screenshot attached.

Steps to Reproduce

Load a custom theme.
Added: Microsoft365Pink

Expected Behavior

The caption area should only display standard window buttons (Minimize / Maximize / Close), with no additional square or ghost button.

Microsoft365 Super Pink.xml

Actual Behavior

Only the standard window buttons (Minimize, Maximize, Close) should appear on the KryptonForm title bar. No additional shapes, icons, or squares should be rendered, even when a custom palette/theme is applied.

Operating System

Windows 10

OS Version

No response

Framework/.NET Version

4.8

Toolkit Version

Nightly

Additional Information

Areas Affected

Toolkit

[mcpbcs]

WinFormsAppSmallSquareRendered.zip
Sample project

[mcpbcs]

Hi @PWagner1

the issue is sill happening. I added a sample form.
Greetings