I installed Lubuntu 16.04, but needed the Gedit editor for programming. Unfortunately when I installed it, it used a GTK window theme that I found to be quite undesirable. I wanted to change the way the max, min, and close icons look. Here's how it looks:
Is there a way to customize this theme on Lubuntu 16.04? Also, is it using Qt, GTK1, GTK2, or GTK3?
According to user ducasse on #ubuntu of freenode IRC, what we're looking at is called a client side decoration by the Gnome developers, and hides the window manager bar and replaces it with something inside Gedit itself. So, no amount of configuring GTK will help in this case.
Other people didn't like this sudden change, either. So, someone posted a way to downgrade Gedit to an earlier version before this dramatic change here:
http://www.omgubuntu.co.uk/2016/06/install-gedit-3-10-ubuntu-16-04-lts
Another alternative, however, is a little harder to install, with a method from Github that lets you customize the existing version:
https://github.com/PCMan/gtk3-nocsd
