Error Window Sizing
When exiting out of the tree editor, if there are nodes that can't be trimmed, a window with an error message listing the offending nodes is displayed. If there are many of these nodes, the window can get quite large. On some OS'es (Windows, for example), the window can get to be so large that the user's can acccess neither the window title bar, nor the buttons to close the window. The error box should have some sort of maximum size built in to prevent this.