If WindowBlinds is launched on my laptop (Win7 x64), 1440 - 900 screen, and then I plug in my external HDMI monitor (1920 x 1080), there is a gap in the texture (only see this with the SD skins) in the middle of app windows. As the app window is resized (smaller than about 90% (guesstimate) of screen size) horizontally, the gap closes up.
This also happens if I set the resolution of my HDMI monitor to 1440 x 900, restart WindowBlinds and then change resolution back to 1920 x 1080 (only did this for testing purposes)
If I go to "Configure WindowBlinds" and re-select the skin, the "gap" is gone.
See screenshots of gap (3 separate shots in one image)
This appears to happen with all apps, it looks like a resizing issue. I can see where the two images mirror each other where they come together in the center. It's like the skin image/texture hasn't been resized/enlarged enough taking into account the full width of the new resolution.
OS Win 7 x64 Home Edition
WindowBlinds version : WindowBlinds 7.42 (325 - Windows 7 Edition) - 64 bit OS
SD stock skins