Right-clicking the mouse gives full maintenance for free

Issue description

This is probably a bug, but my save was going through a crisis and I didn’t have enough maintenance for anything. Trying to get out of the crisis, I accidentally right-clicked on the maintenance symbol and the maintenance filled up completely. I thought it was a quick shortcut to pull maintenance to a factory as a priority, but it didn’t consume any maintenance, so I thought it might use Unity to do that, but I didn’t lose any Unity either. Even though it’s a bug, it can help the factory not collapse, so maybe this bug could persist in easier difficulties perhaps.