I downloaded a Java JAR containing a nice simple paint program (Pixelator). I launch it with java -jar /path/to/pixelator.jar.
I tried to add it to the right-click context menu in Caja, but right clicking on a jpg file, then "other application," then "Use a custom command." I entered the command above, and clicked "remember..." then Open. The program starts with the file opened, but it doesn't show up in the context menu next time.
What might I be doing wrong?