Constructor becomes unresponsive after certain actions

Alright, so after trying to open any CSX file in Constructor, the application becomes unresponsive, and only the menu bar can be used. The window itself is like a still image, sometimes flashing with graphical errors. This happens every time I try to open a previously saved file, as is rather annoying. This also happens when clicking any of the buttons in the "Shapes" section. My only choice is to quit and restart the program.

I'm running Constructor 1.0.4. on OS X 10.10.5. Since Constructor is a GarageGames program, I'll just ask for any suggestions as to what I should do, assuming that no-one here would be able to fix this directly. Reinstalling Constructor doesn't help; seeing as the error is reproducible and is not fixed by reinstallation, it would be nice to see if any other OS X Yosemite users can reproduce the issue.

Is it like a screen with black boxes everywhere and stuff? if so, trying reinstalling it.

It looks like this, it's just a frozen screen, can't do anything, when I do what I described in the op.