I never had the occasion to use your plugin on a real i18n project and boy, did your plugin save me!
I have however the following comments:
1. (BUG) jsp are considered xml files. If I select jsps only in the search 'file types to be searched' criteria, no jsps are returned. However if I select xml only, jsps and xml files are returned.
2. (BUG) todo are not highlighted. This might be a limitation of IDEA. If it is, we should file a Feature request for it. Let me know what it is so I can vote for it.
3. (ENH) integrate unused property inspection with IDEA inspections. Add a quickfix to remove that property.
4. (ENH) allow to rename/move a node of the property tree and have all contained leaves renamed. If I have
Moving the node 'story.disposition' to just top level would result in
Obviously this could be done with rename if it would allow to rename the part of the name from the root to the selected node (in this case 'story.disposition' could be renamed to 'disposition').
5. (ENH) actions should be accessible from the tree. Kind of unintuitive otherwise.
6. (ENH) use Ctrl-B for go to definition that way it will be more integrated with IDEA (you can always wrap IDEA action and remap ctrl-b to your action. Your action would be a pass through to the builtin one except when cursor is in a property name string)