Blurry title bar in Windows 10? Work stopped after updating Windows

Question

I am trying to create a transparent window with a glass effect in Windows 10. This worked until recently:

What I am doing is:

• Paint for the target DC, including alpha. One way to do this in a simple GDI is to create an image with an alpha channel, and BitBlt using SRCCOPY in DC. You can also use the AlphaBlend function.
• Then I use SetWindowCompositionAttribute (or DwmExtendFrameIntoClientArea) to enable blurring in windows 10 (or earlier).

This worked until today and suddenly stopped working after the update - now the window is opaque. I used System Restore and came back once and it really worked again! Any ideas how I can fix this?

Answer 1

Turns out I was calling SetWindowCompositionAttribute . Namely, one of the parameters has a size field, and I entered the wrong size. The fact that it once worked was a coincidence.