Since MacOS/iOS/Linux/Android can not support Boundless switch with CM1942, so the default setting is off. 

If need to use Boundless switch function, please follows below setups.

1. Mak sure CM1942 is in the Dual PC Mode 

2. Make sure all PC connects with CM1942 is Windows

3. Must turn off mouse acceleration and set the speed in the middle in the operating system on both PCs that connect with CM1942

4. Enable Boundless switch function by hot key( [Num] + [-] + [Y] + [Enter] / [Ctrl] + [F12] + [Y] + [Enter] )

5. Configure the screen size of all connected displays via hotkey( [Num] + [-] + [L] + [Resolution (e.g., 3840x2160)] + [Enter] / [Ctrl] + [F12] + [L] + [Resolution (e.g., 3840x2160)] + [Enter] ).

For more information for how to setting Boundless switch , please download the manual from 

https://www.aten.com/global/en/supportcenter/downloads/?q=CM1942

If still have problems, please contact ATEN Tech Support