However, tags seem still to be at least partially case sensitive. I do not see case duplicates in the tags pane. But, when there is a tag "example" on an item, I can still add a tag "Example" without the lower case one being replaced. Also, search does not find tags of they are entered with a different case. Furthermore, coloured tags can only be set to a specific cased keyword. it seems to be even impossible to set colors on tags with other case since they don't show up in the tag pane where colors can be set. Tags should be either generally case insensitive or sensitive. Insensitive is more reasonable IMO.
It seems that duplicate but differently cases tags show up in the tags pane after all. But when new tags are added they only show up after a restart of Zotero...
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"I'm think tags are always case-insensitive now."
However, tags seem still to be at least partially case sensitive. I do not see case duplicates in the tags pane. But, when there is a tag "example" on an item, I can still add a tag "Example" without the lower case one being replaced. Also, search does not find tags of they are entered with a different case. Furthermore, coloured tags can only be set to a specific cased keyword. it seems to be even impossible to set colors on tags with other case since they don't show up in the tag pane where colors can be set. Tags should be either generally case insensitive or sensitive. Insensitive is more reasonable IMO.
Tags became case-sensitive in Zotero 5 — I think not entirely on purpose — and haven't yet been changed to be case insensitive again.
https://forums.zotero.org/discussion/67651/tags-behave-different-in-zotero-5