I have been trying the tags functionality for the first time yet! I have one (possible) bug report and also one suggestion.
So as you can see I have "My library" with just the Text Nut sample text file, that has a tag "MarkDown Test", and then 2 external folders, only "Diario 5" has tags.
So I am not sure if this is a bug, but I introduced several tags at the end of some text files inside "Diario 5". When I go to Tags section, I see them as in the following image.
They just appear there, but no reference to the file they come from. Only the tag "Markdown test" in the TexNut Demo file appears with its reference, I guess because it is in the Library.
And now, as a suggestion, what do you think about this: I have these two totally unrelated external folders: one is a diary I keep, with personal stuff, the other is a folder containing files related with my job.
I think it would be great to be able to just browse the tags for an specific folder. Because to me it doesn't make sense to mix the tags for the diary I keep with the tags for my work-related stuff! And I believe it might be the case for other users... imagine that you are writing two different books, 2 novels, totally unrelated... then you would like to see what are the tags for each of the novels!
Could also be able to click on a tag (in Rich text mode) to see a list of other files containing this tag (inside this folder), so you can jump between files using tags.