Running .53 I did not lose the window, but nothing plays in it, it is just a black window. I can watch the playback in the model preview since I have a group called all-RGB, but nothing shows up in the house preview window. Went back and reinstalled .53. Closed the program and re-opened it. I finally solved all my config problems last night and am working on re-rendering and tweaking my sequences. The preview worked fine this morning, but this afternoon it has gone bye bye. It seems to have happened after I had a second copy of xlights open to look at another setup for comparison.