Hi Bogdan, I noticed your posts here and thought I might mention a couple of things with ExiftoolGUI that you might like to look into at some point.
They are not bugs as such but can cause a little confusion for users
When deleting individual keywords, they can only be deleted in exactly the way they were entered seemingly, so if you enter two keywords at once separated by a comma, eg. 'landscape, mountains' then you can only delete 'landscape, mountains ' and not 'mountains' or 'landscape' individually.
This prevents users from entering several keywords at once, as it appears comma delimited lists are not regarded as separate keywords when entered into the xmp /iptc fields in this way.
Just thought it might be useful to fix this to allow easier entry of keywords and categories.
Nice GUI btw