1. Editing of external files is not part of UR undo/redo, which is for changes to the .urd file.
2. Not directly. The tree control might use some Windows setting for the delay if not specified (it also supports being set explicitly, but there isn't currently a way to set that in UR). What we do is also check
Tools | Options | Trees (More) | Auto-expand only when dragging over item +/- button and then hover over the button only when we want to expand.
3. No
4. Remove .txt and .reg, and add .sql (and any other specific text file extensions to make writeable) to
Tools | Options | Documents | File extensions to open stored documents writeable. .txt is a generic extension that applies to all files classified as text.
5. Create a shortcut and link to that file, or see
http://www.kinook.com/Forum/showthread.php?t=3164