When using HighContrastInverse theme, I see two problems with the color of a selected GtkMenuItem (/!\ “menuitem:hover”):
* “menubar > menuitem:hover”, a selected item in the ones visible all the time in the GtkMenuBar, should not become grey on black (it makes it less readable, whether it is the one item to highlight then…), it should remain white on black;
* other “menuitem:hover”, in the menus and submenus, should have a black CSS “color” on the lightgrey background (instead of a white one, hardly readable here).