Ah HAH! I just figured it out!!!!!!!!!!!!! I can't fix it, because I think this is something Stardock has to take care of, but here's the deal.
Now that there is WB5 around, Skinstudio (and presumably WB5) appear to assume that skins have per-pixel window borders. I poked around in Skinstudio and realized that every single WB4 (or WB5 not using pp-transparency) skin has now gained a section in the skin called "Window Borders-PerPixel"
This is not a problem for skins like Simple Alpha that were designed with WB5 in mind. However, the majority of WB skins out there are NOT designed for WB5 and do not have images defined for this section!!
This is a huge huge huge problem because Windowblinds appears to be looking to the Per-Pixel section for even the normal "Maximized Active Window" properties! This is overriding the skin's prior setup which just defined top, left, right, bottom borders under the "Window Borders" section, so since the author did not define the images for the separate section under "Window Borders - Per Pixel > Maximized Caption", WB5 sees that there is no such image, so it makes the window titlebar (aka caption) have 0px.
That is why the titlebar goes missing all the way above the screen--WB is trying to show a non-existent graphic.
Now, I'm not a skinner, so I don't know how to fix this, but it seems like this is a pretty big issue that Stardock out to address. Right now the vast majority of Windowblinds skins are still for WB4 and all of these are fairly unusable because maximized windows lose their titlebars!
We don't seem to be getting replies to this topic and to one I had posted earlier today. Is there any way we can bring this to Stardock's attention?