I have one file for the mountain above our club and I start having a long list of caves in my file (40 and increasing...). So in order to keep thing net and tidy, I would like to be able to group caves by catchment area. At the moment, I use the cave numbering and I create a fake cave to use it as a group title (---------- GROUP NAME --------) to clearly separates each catchment area but this is not the most practical. If we could get the possibility to group caves, expanding or collapse the groups, select to display everything in one group... it would be great. Is that something doable?
First of all, the cave list is technically a "list" and not a "collapsable tree". Your workaround is the best you can make of it.
For grouping we need a new name field in the cave data (for group/area/status/...). With some kid of filter you could reduce the cave list to the caves with the filtered name. Sounds not agreeably yet.