For the benefit of someone coming along in a year or so hoping to find answers. I had a similar problem to the "screen freezing" issue described in the video.
What it turned out to be (for me) was that there was a popup window that asks to insert tool X and click OK. For some reason that window stayed in the background. Changing Linux CNC to not be full screen allowed the window to come to the foreground.
That was the solution in MY case.
