Run Eclipse in GTK2 mode

https://coffeeorientedprogramming.wordpress.com/2014/10/27/how-to-tell-if-you-are-running-eclipse-on-gtk2-or-on-gtk3/

If you are having trouble with the appearance of Eclipse, maybe running it in GTK2 mode will solve some issues.

To solve that, run Eclipse with the following command:

env SWT_GTK3=0 eclise