Hi,
Although I don't know the reason, the GTK3 backend of SWT is of questionable quality, I recently did some benchmarking and at least for the operations tested it delivered 1/3 of the performance SWT+GTK2 delivered: https://bugs.eclipse.org/bugs/show_bug.cgi?id=493714 To some degree this is because the code is still quite fresh, on the other hand GTK3's ever-changing interfaces as well as years of development without any continous performance + regression tracking seems to show
You can force SWT to use GTK2 by exporting SWT_GTK3=0, works like a charme on all my systems.
Best regards, Clemens .