iTerm2: Split pane - coloured title bar instead of dimming

In iTerm2 it is possible, to split panes. Thus, I have parallel multiple terminals instead (or in addition) to tabs. This is very similar to the i3 Window Manager or Terminator Terminal Emulator.

When having multiple terminals, I would like to quickly know what is the active terminal. iTerm2 has an option to dim, but this is not so great because inactive terminals are not that good to read (e.g. htop).

It seems there is no option of using coloured title bars (not tabs!) based on active pane/terminal. Only programms can do so via escape codes). Does anybody know a hack for this or is up to me to request an enhancement? Maybe I overlooked it...

Thanks, Timo