In EESCHEMA, the response is very slow or sometimes frozen when zooming in or out using the mouse scroll wheel.
I wonder if it is related to the graphic engine because in PCBNEW the OpenGL canvas is a little faster than the default. But, there is no way to choose it in EESCHEMA.
I tried in Ubuntu 16.04 and 14.04. The graphic card is AMD Firepro 2270 and its driver is by default of Ubuntu.
Also remember:
This is a user forum. Very few developers visit it regularly. Some might have experienced the same problems you have and might know a workaround to get better results.
If you want direct interaction with developers, head over to the bugtracker. Read the “how to report a bug” first.