So I updated WACUP to the latest public preview last night. Left my skin as is, MMD3, before the update.
Came back to a buggy looking UI with no text displayed in the Media Library window, and Right Click context menus too thin to read or work with.
It was unstable, so I had to force quit it through Task Manager.
Backed up my settings, uninstalled, and reinstalled this morning. Replaced my preferences, didn't replace my skin folder.
It was working with the default Big Bento Modern skin, so I tried reinstalling MMD3 again.
No text in the Media Library window, too thin text in right click menus, instability returned.
Attempting to return to return it to Big Ben Modern by accessing preferences through Ctrl + P shortcut and reloading it now gives no text and unusable menus.
Removing MMD3 restored Media Library text and Menu functionality.
For extra fun, I installed two other skins with a non-default appearance-- Peanut, and HM1 Touch.
Both worked out of the box.
Of note, this WACUP build didn't automatically associate WAL files with it after my reinstall, a problem I fixed by select WACUP as my option for opening *.WAL files.
Also, whenever I tried installing a skin, WACUP would warn me that the skin install was stopped midway through, and let me try and continue loading it. MMD3 didn't work, Peanut and HM1 Touch did.
Regardless, reporting this as a WACUP problem as MMD3 was working fine before the latest Public build.
Attached are files showing Big Bento and its menu after attempting to load MMD3, MMD3 after its reinstall and first time loading the skin, along with its menu, the skin install error, and HM1 Touch.