I've been using a WB skin with transparency since WB 6.x. The last stable version I used was WB 7.4. However, after I upgraded to WB 8.01 beta, I noticed sometimes apps lose their titlebar and frame completely. Restarting the app fixes the issue, at least for a while. I'm not sure if this issue is a known issue; or, maybe, indirectly related to another reported issue or not. Anyway, I thought I'd at least mention it here.