I just got a new notebook with 4K display and do some testing.
The lazarus IDE itself is not suitable for high DPI yet.
then I uncheck the DPI Awareness checkbox and rebuild the IDE, now everything looks fine.
I also check PixelPerInch in object-inspector for the default form, it is 96. I think is a reasonable value for development.
Shall I create a bug report for this ?
Looks like I post in wrong place, someone please move it to proper place.