Experimental Physics and
Industrial Control System

It would be helpful to know what the issue you had actually was.  If we understood what the issue was, we might be able to make sure that was tested so it could not happen in the future.  At this point, I do not have the slightest idea what the issue is.  You have not provided any example code, even when explicitly asked to do so.  You say it is related to a GUI toolkit, but have not even said which toolkit that is.

The PR you point to maes many changes.  You say the problem is "probably thread race condition" and maybe that is correct, but did not give evidence supporting this claim.  You also say it is specific to Python 3.5.  Maybe that alleged race condition is actually a problem with some other library?   

Again, please provide an example that shows the problem you are having.

--Matt