Well, the name 'Plugin' is a bit too much, but I wanted to stick to the naming convention...
.h2 Ultra Edit
UltraEdit is a nice little text editor when working on Windows. It is very much suited to handle all kinds of resource files and some little scripts, when starting your IDE just takes too long.
You can get it from http://www.ultraedit.com/
UltraEdit is not free but fairly unexpensive. One can work with the evaluation license foreven, but the warnings get more and more annoying then.
.h2 Running Groovy scripts
The first nice thing is to edit and start any groovy script from inside the editor. When doing so and you get a stacktrace, it is added to an output list, that is click-aware. In the line you click, UltraEdit tries to find a filename and a line/column position and opens the editor at that position.
To make this happen, go to Advanced -> Tool Configuration and enter the following: