Issue title: Minor bug: Glitch when simultaneously right and left clicking
 Issue body: I had the upgrades screen opened and moused over the X. I then accidentally simultaneously (or nearly so) clicked with the right and left buttons.

The upgrades window button was unresponsive to any more clicks.

Pressing the F key to toggle the upgrades window worked. Further use of the upgrades window works fine.
 Comments: 
 Comment 0: Fixed by that pr :)
{'source': 'GithubIssues', 'repo_name_with_owner': 'tobspr/shapez.io', 'issue_id': 639780923, 'repo_stars': 5314.0}