This is something I discovered recently when I fresh installed a new Windows 11 24H2. When I uninstall Start11 the issue is gone. With Start 11 installed and Windhawk uninstalled, the issue is there. It is just creating a full width semi-transparent black bar on top of the original taskbar when I hover it. I would say Windhawk itself is compatible with Start11 since it is just providing a way to inject codes into the process, but some mods may not be.
I have managed to apply a fix in my mod. And here is what I found:
- Something is taking over tray rendering behavior for:
- Shell_TrayWnd
- DesktopWindowContentBridge
- During hover/flyout transitions, the process is repeatedly wrote tray accent policy via SetWindowCompositionAttribute with:
- WCA_ACCENT_POLICY (Attrib = 19)
- ACCENT_ENABLE_TRANSPARENTGRADIENT (AccentState = 2)
- dark gradient color
- That accent write is what produced the unwanted full-width background behavior
I added a patch in SetWindowCompositionAttribute hook that:
- (Only) when
- target window is Shell_TrayWnd
- Attrib == 19
- AccentState == 2
- Force GradientColor = 0x00000000 (transparent)
Which fixed it. Not 100% sure if this is from Start11 but I think this might provide some data point for a deep dive.
