Mouse input on appVM on second monitor not working


I am having an interesting issue: I connect a second monitor to my laptop via HDMI (I configured it to be an extension to the right, not a mirror) → it is well recogniced and shows my desktop.

I can move windows onto the new screen, I can move my mouse there. However, if I move the window of an appVM onto the second screen, where the appVM was started before connecting the monitor, it does not accept mouse inputs (keyboard works). If I start the appVM after connecting the monitor, it works perfectly fine. Standalone Qubes are not affected by this.

So it seems to me that the appVM has to receive an update on the available screen surface, which does not happen currently. Does anybody have an idea where to look further? Is that behaviour desired (for some security reason that I cannot think of) or is it a bug?

thanks and best regards,


I recall and old forum thread about this issue (within the last year?) - some kind of “new max desktop size not send to running qubes” (?).

I’m hit by the same problem, when I dock in the office … if a qubes was started while not docked, the mouse will not work on the right screen. Qubes started while docked, will work (also after undock ; redock). Sorry that I can’t locate the old topic … :-/

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Hi ChrisA, thanks for the answer. I found now this thread here: External Monitor Input where reboot is the solution - however that is not really satisfactory for me. Was that the thread you referred to?

I don’t think so - I’ve tried to find it, but so far failed to do so. :-/

I recall some more posts, including something like X11-resize-message/event (?) that didn’t make it to running qubes. I’ll try to search again at a later time …

Is it a 4K monitor? If so, you likely need to increase VRAM.

If not, see this issue.