VirtualBox guests stop seeing keyboard after screen locks on Manjaro Xfce host

Question

The problem is when the Manjaro Xfce host does screen locks.

Only screen locks trigger this behavior. It is when I have to enter the password to unlock the screen.

I've tried to put my screen to sleep with "Blank after", "Put to sleep after" and "Switch off after".

If the "Automatically lock the session" is disabled then VirtualBox guests see the keyboard after screen awakening.

If it is enabled then guests loose the keyboard after screen awakening.

Other windows of Xfce Manjaro host do not loose keyboard focus in the same situation (if they have it). Let's say, if the Text Editor is open then I can continue to type a text into it after screen unlocking.

I use the latest Xfce Manjaro with the latest updates. It was tested on kernels 5.4, 5.9, 5.10.

Workaround

To restore keyboard connection on a VirtualBox guest you may

• Switch to another opened window of the Manjaro host and jump back to you guest windows.
• Click the Application (Start) button of the host desktop and jump back to the guest window.
• Minimize and reopen you VirtualBox guest window.

Ubuntu behavior

On Ubuntu, screen sleeping is automatically disabling if a VirtualBox guest window is active.
Ubuntu shows a warning that another applications locks screen sleeping.
I.e. your screen will never be locked, let's say in a public place. I definitely prefer the Manjaro Xfce behavior.

This would be great to know how to fix this keyboard loosing on Xfce Manjaro.

BTW, MS-Windows hosts has none of these troubles of Ubuntu and Manjaro Xfce.

I'm using the Manjaro as VirtualBox host because it allows my laptops to behave as a tabled. It is because coolers are silent most of the time despite a quite big load.
Of course this is not the case if I run a pair of heavy IDEs in a pair of heavy VirtualBox guests.
Neither Ubuntu nor Windows can give me this beauty.

Answer 1

I have been getting this lately in Virtual Linux Mint Xfce within Linux Mint Xfce, and none of the workarounds worked for me - I've been having to power off the VirtualBox because it was getting stuck - no ctrl-f without a keyboard. But today I just went with it because I needed only mouse input for hours - and found another workaround - I got an email - and clicked on the email popup notification from the outer Mint that is visible on top of the VirtualBox - that brought me out of VirtualBox - and then when I went back, the keyboard was back! So I think you can email yourself from your phone, click on the email popup notification you get, go back, and see if the keyboard works again! Perhaps it goes without saying but another workaround is to exit full screen VirtualBox before you walk away from the computer.