[UI] The dirty/close decorator is broken in IDE

[kittaakos]

Describe the problem

The dirty/close decorator does not look good when I hover over

To reproduce

• Create a new sketch,
• Disable auto-save,
• Click on the Debug icon on the left,
• Click on Start Debugging (the play button),
• Editor opens and it's dirty, and
• Hover over the close icon.

closeable_widget.mp4

Expected behavior

The X is visible when hovering over the dirty decorator.

Arduino IDE version

Version: 2.0.0-rc7 Date: 2022-06-09T08:19:19.877Z CLI Version: 0.23.0 [899dc91b] Copyright © 2022 Arduino SA

Operating system

macOS

Operating system version

12.3.1

Additional context

No response

Issue checklist

• I searched for previous reports in the issue tracker
• I verified the problem still occurs when using the latest nightly build
• My report contains all necessary details