I recently updated my gVim to version 8 compiled with gtk 3, and I found there are strange inner borders around the gVim window:
This picture may not very clear but if you look carefully you can see the white borders on the right side and the bottom. I have solved this issue by setting a dark color to the border on gtk 2, but on gtk3 it happends again. Any idea of removing this border completely on gtk 3?