As indicated in the thread below, Chrome pushed an update that is causing issues with pop-up positions.
Also, I just found-out that when you are in Live-Testing mode and are debugging and use the DoIt, the pop-up result is just blank (well most of times). Even the updates in  doesn’t seem to address all issues.
It seems that the latest version of Firefox (56) is fast, and doesn’t have these issues. If you use Chrome and have these issues, please switch to Firefox