Musescore's broken after new update

I just installed the update, and so many things no longer work how they used to, making it incredibly difficult to use the program.

1: Any and every pop up window opens on my second monitor.
2: When creating a new score, on the "Additional score information" page, I'm completely unable to change the key signature, the time signature, the tempo, and the number of measures. Those dropdown menus for the corresponding icons are just nonexistent. They don't even open on my second monitor.
3: Clicking on any tab in the top left causes it to open that tab's dropdown menu on my second monitor.
4: Right clicking opens the context menu on my second monitor, instead of where my cursor is.

I want to be clear, this was never a problem for me with the version I was on before. How did any of this make it past software testing, and when will it be fixed?