Running GIMP on my KDE desktop the tooltips are all white-on-white. How do I fix this?
To quote this answer by Narcolessico to the generalisation of this question on Super User, i.e. https://superuser.com/questions/1100408/tooltips-of-gtk-applications-are-unreadable-within-kde:
The issue is due to a partial override of GTK colors by means of KDE style.
System Settings > Colors, deselect
Apply colors to non-Qt applications, restart the GTK application (e.g. Gimp). This breaks the feeling that all applications share the same style but tooltips will be again readable in both Qt and GTK applications.
Anyone wanting fine-grained control should probably use https://superuser.com/a/1190633/571648, which tells you which configuration files to edit, though their location seems to be different on my installation.
Go to KDE system settings, then pick Application Style, then pick GNOME Application Style (GTK). For both
Select a GTK2 Theme and
Select a GTK3 Theme choose
HighContrast, then click on