Problem is assigning a New Tab shortcut to CTRL+ALT+N because on some
keyboards (in this case Croatian layout) it conflicts with the end-brace
symbol.

Croatian keyboard layout uses "right alt" or "alt gr" for extra symbols and
it works by combining CRTL and ALT in one keystroke. This sould be a
problem with many Eastern European keyboard layouts.

what does firefox use as its shortcut for tabs with those keyboards?

CTRL+T, the same as everywhere else in the world, but it's connected to
autoformat in processing.

You could use CTRL+SHIFT+N as an alternative solution. There should be no
issues with CE keyboards.

Please avoid CTRL+ALT combo in the future because most CE layouts use it a LOT.
Croatian layout example:
+F = [
+G = ]
+V = @
+B = {
+N = }
+Q = \
+W = |
+E = €
etc.

well, i try to tune the key assignments to offend as many people as
possible. just cuz i enjoy gettings messages like this.

i'll see if i can figure out a workable set of options for the next release.

removing shortcut for rename, changing new tab back to ctrl-shift-n.