When you press ALT + Tab button in Windows 10 to switch, you can see the grid background is fully black, and the background of windows with desktop icons are visible. It can be made fully transparent with a registry tweak.
How to Hide Desktop Icons and Windows in Alt + Tab?
1. Click on Start button and type the regedit.
2. From the search results, click on regedit (run command) to open the Registry Editor.
3. Navigate to the following key:
4. On Explorer, right-click and select New > Key
5. Rename the new Key as MultitaskingView.
6. Right-click on MultitaskingView and again create a new Key, and rename it to AltTabViewHost
7. Now, under AltTabViewHost, create three new 32-bit DWORD Value, and rename it as the following:
8. Double-click on the wallpaper to edit its value, and change from 0 to 1.
Now when you will press ALT + Tab button, you will be not able to see Desktop icons.
How to Make ALT + Tab Background Transparent?
By default when you create Grid_backgroundPercent, its value is 0, means your background will be fully transparent. You can modify it by double-click on it. Here value 100 means full opaque. You can choose any value from 0 to 100, according to your choice.
If you want to dim the background wallpaper (not the grid background) and to set the opacity as required. You can change the value of BackgroundDimmingLayer_percent from 0 to 100.
You can also download ready-to-use registry file.