I'm currently making a screen dimming program in C# that uses black winform forms with an adjustable opacity to dim the whole display. This by itself is unable to dim certain windows UI elements such as the start menu, alt+tab and win+tab menus. In order to be able to dim these menus I've declared the program to be accessibility as described in the top answer in this stack overflow post . My program is currently: Declaring level="requireAdministrator" and uiAccess="true" in app.manifest. Calling topmost = true; in my overlay forms. Signed using a self-signed certificate. Running from Program Files. By doing all this my program is now able to draw on top of the previously undimmed menu's. However, when opening and closing the start menu and context menus in the taskbar, switching virtual desktops using win+ctrl+left/right arrow, everything outside that windows UI element get dimmed twice until the UI animation finishes. I'm assuming windows draws the overlay form twice during the UI animations, once underneath the windows menu elements and once above. Is there any way to prevent this behavior?

Winforms screen dimming overlay program gets drawn twice when opening/closing start menu or context menu's in taskbar

XiaoYiHu-6776 0

I'm currently making a screen dimming program in C# that uses black winform forms with an adjustable opacity to dim the whole display. This by itself is unable to dim certain windows UI elements such as the start menu, alt+tab and win+tab menus. In order to be able to dim these menus I've declared the program to be accessibility as described in the top answer in this stack overflow post. My program is currently:

Declaring level="requireAdministrator" and uiAccess="true" in app.manifest.
Calling topmost = true; in my overlay forms.
Signed using a self-signed certificate.
Running from Program Files.

By doing all this my program is now able to draw on top of the previously undimmed menu's. However, when opening and closing the start menu and context menus in the taskbar, switching virtual desktops using win+ctrl+left/right arrow, everything outside that windows UI element get dimmed twice until the UI animation finishes. I'm assuming windows draws the overlay form twice during the UI animations, once underneath the windows menu elements and once above. Is there any way to prevent this behavior?

Jiale Xue - MSFT 43,046 Reputation points Microsoft Vendor

2024-02-13T02:39:45.21+00:00

Hi @XiaoYiHu-6776 , Welcome to Microsoft Q&A, Try delaying your window drawing until the Windows UI animation is complete. You can use a timer or other means to detect the UI animation status and draw your window after the animation is complete.
XiaoYiHu-6776 0 Reputation points

2024-02-13T10:25:28.8533333+00:00

Hi @Jiale Xue - MSFT , thanks for the answer! Do you know of any way in C# to detect the UI animation status other than checking for key presses?
Jiale Xue - MSFT 43,046 Reputation points Microsoft Vendor

2024-02-14T09:05:09.8933333+00:00

Hi @XiaoYiHu-6776 , Yes, there is no direct built-in method in C# to detect UI animation states, such as animations of Windows UI elements such as the Start menu or taskbar. However, you can indirectly infer the UI animation state by monitoring changes in the visual appearance of the system. You can use two screenshots to compare. Considering your usage scenario, there is no good way.

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Winforms screen dimming overlay program gets drawn twice when opening/closing start menu or context menu's in taskbar