Have you tried changing the scale of the programs and apps etc to 100%. I had this problem using a 4k monitor with the recommended scaling of 150% for apps and text. Temporarily changing the scale of those to 100% solved the problem. The developer is aware of the problems with 4k monitors. but told me the solution will not be soon. On a 2560 x 1440 display I find it works fine if the apps and text are set to 100%