All tool buttons are shown as disabled
This is Gimp 2.10.6 on Windows 10.
When I create a new image or open an existing one, all tools in the toolbox are shown as disabled.
This is confusing. The tool icons use the same color as the background (the fox image just below the main menu), and because it is disabled, clicking on the fox image does not have any effect.
But even though the tool buttons are disabled, hovering over them changes their background to blue. And, furthermore, clicking on the buttons has exactly the same effect as if they were enabled. But they are clearly shown as disabled, so something must be wrong here.