Steps to reproduce:
1. Create new Unity project using Universal 3D Template
2. Go to Preferences > General > Editor Theme and switch it from Dark to Light
3. Observe the toolbars where window tabs are located (Hierarchy, Scene, Inspector, Project, etc.)
Actual results: Toolbars remain black/dark and doesn’t adopt the Light theme, even though the Light theme is active. Hovering over a tab causes it to briefly render correctly in the light color, but tabs revert to black once the mouse moves away
Expected results: Toolbars should render in grey/light coloring consistent with the rest of the Light theme, matching the same styling seen on hover.
Reproducible with versions: 6000.7.0a2 (83605ec097c0)
Not reproducible with versions: 6000.7.0a1 (0fe3875ef801)
Tested on (OS): macOS Tahoe 26.5.1 (M1), Windows 11
Notes: The issue is also visible in Dark Theme and not only in tabs area. This affects: dropdown options, color picker windows, etc.
There are visible issues in windows (e.g Multiplayer Center, Shader Graph Template) where titles are not fully visible or search field doesn't alight, cutting the filter buttons