Programming blocks can be lost at the top of the window.

[Jeffrey Elkner]

It is possible to drag a block under the Gnome window menu bar (the one with File Edit View Tools Turtle) and then not be able to grab the block afterward. The block essentially gets lost off the top of the screen. I'm not sure if TurtleArt still considers the block to be part of the program, but I think it does, since that would explain students showing me simple programs that give errors every time they are run, even though I can't see anything on the screen that would be causing and error.