SpriteFont editor freezes Construct when importing new image

I've been experiencing an issue when importing an image file for the SpriteFont object, Construct will randomly freeze and I'm unable to close the image editor resulting in the entire page being frozen. The only solution is to refresh the tab, resulting in losing work unexpectedly if I don't remember to save constantly.

If you can reproduce this with a small demo project, you need to log a bug report:

github.com/Scirra/Construct-3-bugs/issues