Zutilo shortcuts?
Defining the Zutilo shortcuts shows a strange behavior on my iMac (10.14.6): sometimes a defined shortcut is functional, sometimes not, even though it is accepted in the panel. Sometimes choosing a letter from keyboard makes a different letter or mark in the shortcut. This can also work or not. My Zotero is in Finnish and Zutilo is in English. Is this the reason?? There doesn't seem to be a shortcut for opening a pdf associated with an item. That would be very useful.
https://github.com/willsALMANJ/Zutilo/issues/122
https://github.com/willsALMANJ/Zutilo/issues/136
For testing whether your issue is related to the Finnish locale, switch your language settings in the Zotero preferences to English.
It's best to use github for reporting on Zutilo issues, such that the Zutilo developer will be updated.
To me, Zutilo turns out to be practically useless: I tried all kind of letter + cmd/opt/ctr combinations for Item pane: Focus Tab tag and nothing worked. I just managed to get 4 shortcuts working: Advanced search, cmd+S; Item Pane: Focus Info Tab, cmd+I; Item Pane: Focus Notes Tab, cmd+N and Item Pane: Focus, cmd+U. Moreover, the site for cmd+N in the Shortcuts table became empty, there isn't that cmd+N, even though cmd+N works. Surprisingly, when I tried different letter-command key combinations for Focus Tab tag they were usually accepted but worked like cmd+N! Strange!
It would be very welcome that the shortcut feature would be made working, as using mouse is slow, laborious and causes wrist strain.
https://github.com/willsALMANJ/Zutilo/issues/137 Try a different keyboard shortcut for adding tags, one that is working for another function. You have to disable the other function's shortcut for this test.
2. Did you try using a different keyboard shortcut for the "add tag" function as I suggested above?
3. For debugging the "add tag" issue further, you could try the following:
a) Disable all add-ons. ("Tools" -> "Add-ons".)
b) Check if adding multiple tags in pure Zotero works as expected when using the Enter key.
c) Enable Zutilo and check if the problem is directly related to it.