If you have the regular Windows 11 Remote Desktop app open and have your mouse cursor in there, it seems the Multiplicity hotkeys to switch to another machine and broadcast are swallowed by the Remote Desktop and do not allow you to switch. I can reproduce it by clicking the mouse into the Remote Desktop and then pressing the hotkeys to switch to another computer. They don't move the mouse cursor to the secondaries.
If you truly mean 'Seemless Display' (not just a Seamless connection), then what you are seeing follows, its not switching to a Secondary anymore, any hotkey needs to be set up to switch to a monitor, not a Secondary. Remember, when using a Secondary monitor for Seamless display, its not a Secondary anymore, its an additional monitor. You could create a new key to go to that monitor I suspect but it would not be to go to a Secondary.
There's also an issue with Remote Desktop and the broadcast key. If I am in a Remote Desktop (running Gnome in Linux) and move my mouse via Seamless mode to a secondary, I can do the custom broadcast keystroke (CTQL + Q). Broadcast works. However, then when I try to stop broadcasting from the secondary via the keystroke, it does not work. The only way I can stop broadcast is to move the mouse to the primary and click out of the remote desktop window and then press CTRL + Q.
To be clear, in Seamless mode, you open an RDP session on it. If you start recording, no doubt, the RDP session does not have focus (the Secondary has the recording software). The same is true when you want it to stop, the Secondary, not the RDP session on the Secondary, needs to have focus for the keystroke to register.
Sean Drohan
Stardock Product Lifecycle Manager