I find the tag palette a bit cumbersome when I am adding hierarchical tags. I expected to be able to drag tags onto the parent tag, or better still create a child directly.
I went to the file list under tags, and was of course able to drag them there, but thought i would be able to create a tag there clicking on the plus sign when the tag was selected. (It creates a folder.)
It makes creating hierarchical tags a two stage process, and is not totally intuitive.
Wonder what you are planning on this for next version.
I am planning to make the + button context-sensitive (not sure if this will make the next version), but in the meantime you can create a child tag directly using File > New Tag when you have the parent selected in the source list.
As of EagleFiler 1.1.2, the + button can create new tags. If you have tag selected, it will create the new tag as a child of that tag. If you have the Tags folder source selected, it will create a new top-level tag.