The tooltip text is always black. For some reason, the default tooltip background colour is also black, which results in black text on a black background. You can change this by going to
System Settings > Application Appearance > Colours > Colours
If you change the background colour to something bright, you will be able to read the black text.
Presumably this needs to be fixed in the KDE defaults.
The tooltip text is always black. For some reason, the default tooltip background colour is also black, which results in black text on a black background. You can change this by going to
System Settings > Application Appearance > Colours > Colours
If you change the background colour to something bright, you will be able to read the black text.
Presumably this needs to be fixed in the KDE defaults.