I sadly have not much time this and the next week but i was able to test a bit:
Windows 10, resolution 1920x1080 and 100% scaling everything looks fine. Even better than in eclipse (no blurry text)
I can not say if there is some to big space of the toolbar or around the controls, this simply does not jump into my eye....
One thing that bothers me is that there is no message box that says you have to restart codeblocks for the changes to work. I also do not have disabled any dialog, so is there one? If not it should be introduced...
As i said top i have not much time for the next weeks ;(