PHPStorm in multi monitor multi DPI environment on Windows doesn't scale on second screen



I use PHPStorm on my Dell XPS 13 notebook with 4k display with 220% scaling connected to an full hd monitor with 100% scaling. The full hd monitor is my primary monitor. PHPStorm ist correctly scaled and sharp on my primary monitor. If I move a PHPStorm windows to my secondary 4k screen (notebook display), the PHPStorm window is still rendered with 100%. Because of the 4k resolution the fonts and the GUI are so small and tiny that it is unusable.

What can I do, that PHPStorm scale correctly on second screen too?

Regards, Kristian