The plug-in "gedittools" comes along with
- XML Highlighting on double click
- Highlighting of selected in whole document word on double click
- Counting occurances of selection and showing results in statusbar
- Launching "meld" as DIFF tool based on selection of opened documents

To use this plug-in ...
... copy all files to ~/.gnome2/gedit/plugins
... activate the plug-in in gedit settings
... configure plug-in to select needed features
... optionally install meld to make use of meld launcher. See below.

To use meldlauncher, do this:
... install meld. On Ubuntu do this: sudo apt-get install meld
... open 2 or more files and hit the new compare button in the toolbar.


Have fun!
