mouse cursor moves but cannot click with 20.04LTS

I am on Kubuntu 20.04LTS. KDE Plasma 5.18.5

Today, I found that the mouse cursor moves but cannot click at all. Sometimes the wheel works (exchange desktops) but sometimes it doesn't. Sometimes the mouse cursor is constantly shown as I beam style, sometimes it changes to arrow style and I beam style depending on where it is. Selecting on the Desktop by dragging the mouse never works. The keyboard always works.

After entering virtual desktop by Ctrl+Alt+F3 and exiting by Ctrl+Alt+F1, the mouse click starts working. But I have to perform Ctrl+Alt+F3 and then Ctrl+Alt+F1 every time after booting my Kubuntu.

I removed virtualbox-6.1 and checked if the issue got fixed, but that didn't fix it.

Is there anything I can do to fix the issue?

Solution 1:

So far I found nothing to resolve the issue.

But once happening the issue,

1. Press CTRL+ALT+F3 to go to a virtual console.
2. And then press CTRL+ALT+F1 to return back to gui screen.
3. As a result mouse click back to effect.

Currently everytime when mouse click lost, I do above.

Solution 2:

Not really an answer, but another workaround... For me on ubuntustudio 20.04 I have to Ctrl-Alt-F1 to go to a console, then login and 'sudo pkill lightdm' to kill the display manager, then Ctrl-Alt-F7 to switch back to the GUI and login again. Of course that kills all my windows, but the mouse click is restored.