Just another problem I should have reported a long time ago. It has followed me through the last year or so of any updates so I don't know if it's just me or if it's just something no one else has reported or I just didn't find the reports when I searched.
Anyways 99.9% of the time if I have Stardock Central OR WinCustomize application skinned when I'm browsing through the new Skins and Themes, the Large Preview window will disappear (not really gone just not accessible at the moment). For some reason it just isn't accessible until I either restart the applications, windows, or unskin the application I'm in be it either Stardock Central or WinCustomize.
Kind of a kicker when these are the programs that are supposed to be showing this stuff and I can't have them skinned lol. I've basically set them both up to not let Windowblinds skin either one of them for now, every once in a while I take it off and try again and end up unskinning them again for a while. Been this way for a very long time, at least a year or 2 for me. Hopefully it's not just something wrong with my install cuz I don't want to reinstall it again if I don't have to lol, I just did that a few weeks ago and lost so many settings so hopefully this will be a bug that is fixable.
Thanks for checking into this and hope to hear some good news on it soon

P.S. I did try posting this in the bugs section of the discussion area via Stardock Central but it wouldn't let me hit enter to start a new paragraph and I hate having one huge long paragraph to read so I didn't want to do that to you either lol, please move the post if it's in the wrong place and sorry if so.