what IDE is best for a multi-monitor/multi-window setup?

[Setigerous]

I'm trying to make this thing for Apknite and IDE is actually 
overkilling for me, all I need is:

A text editor

breakpoints - easy debugging

IntelliSense, or any good enough auto-completion

I've used MonoDevelop (the last version to work was 5.10, and it 
was way too buggy). I would still use it, but the old DEB I saved 
no longer installs on newer Ubuntu versions.

I've also used dlangide, it's good, works well, except, the newer 
versions don't compile, and even if you make the newer version 
compile by making changes suggested in its issue #308, the 
autocomplete is broken. And I don't think it supports 
multi-window setups.

And I'm on a ubuntu system, windows solutions aren't for me. As 
I've mentioned, any good text editor that has:

usable autocomplete (unlike geany)

GDB integration for debugging

what IDE or text editor would you suggest?