Hello,
I was struggling with the issue and doing the following seemed to have fixed it for me. I had been using dual keyboards with microsoft IME (Korean and English)
Start -> Edit Language and Keyboard Options
1) Make sure English is set to default.
2) REMOVE foreign language keyboard(s). Annoying, I know, but this is what fixed it for me. Just a temp fix until Obsidian can fix the issue.
I restarted my computer just in case, and the game runs perfectly now. No mouse click errors.