Sometimes whilst working on my design the keyboard shortcuts stop working … or at least some of them do. I haven’t tested thoroughly but often the Select (spacebar) won’t work along with one or two others.
The only way to fix it is to save then close and restart.
Hey Wozza; I’ve heard of this problem before. We’d love to learn more about it. The next time this happens to you, would you be willing to take a screenshot of the developer console in your browser? In Firefox, you can pull this up via Tools > Web Developer > Web Console.