I realize that this is most likely not the ideal place to pose this question, and that it is probably not at all related to Plugable products, but I struggle to even describe it properly and thus don’t know where to look or Google for a solution. So this is a desperation move, hoping that you’ve encountered this before.
I am using this switch to share two Windows 10 PCs with the UD-3900 in a dual monitor setup. I have Windows apps open in both monitors. Each cable that is connected to the switch is USB3 at each end. When I switch from one PC to the other, using the USB3-SWITCH2, then switch back, all of the Windows programs revert back to being displayed on the primary monitor. Is there a way to preserve the location of all the Windows apps so I don’t have to manually move them back each time?
In short, the behavior you describe is expected and can affect anyone disconnecting and reconnecting an external display from a Windows 10 system (even when Plugable products are not in use). We are not aware of a workaround for this behavior when using Windows 10, however the next version of Windows (Windows 11) appears to have a solution.
To expand further, when you disconnect an external display from a Windows 10 host PC (as you are in effect doing when pressing the button on your USB Sharing Switch) Windows will ‘move’ all of the open application windows that were located within the external display to a display which is currently connected and active.
Unfortunately, when you ‘reconnect’ the external displays (such as when you use the USB switch again) Windows will not ‘move’ the application windows back to their previous location on the external displays.
When this feature is enabled, application windows will behave in much more helpful and logical manner (as compared to Windows 10) in that applications will return to their original positions on external displays when those displays are reconnected.
In summation, while we unfortunately are not aware of a workaround to the behavior you describe while using Windows 10, the next version of Windows (Windows 11) has a new feature that can help.