Dash mode ⊗⊖㉤ window buttons have varying luminance
When the Dash is opened (pressing <Super>), three symbolic variants of the window manager icons are used.
With the current icons, the left ⊗ (red) icon has strong contrast against the background, as does the right-hand ㉤ (white) icon.
However, the middle icon has very low contrast against the background, and is also much dark. This creates visual variance.
I believe the shading is to show that the icon is disabled and unavailable, but this is not immediately obvious, and looks more like an oversight.
Perhaps it would be possible to hide the minimise ⊖ (grey) icon completely?