Comment 30 for bug 405426

Weltall, I think the important question here is why you have 9 windows
open over such a small space. Workspaces are your friend!

The change may have been nicely accompanied by left-aligned titles, to
make the windows easier to pick apart.

This discussion should really be moved to a mailing list, but I'll bite:
The benefit to removing the icons is simple. With an icon, it is not
obvious to users that they can click there for additional
functionality. This functionality is actually really useful, including
keeping a window on top. Lots of cool stuff. So, by replacing that
icon with a proper, neutral button-like thing, it is more apparent
what it does.