My practice is to make all tags lowercase. As a result, the only “tag” that begins with an uppercase letter is “Untagged”.
I acknowledge how microscopic of an inconsistency this is, and I have no issue living with this limitation (if that is in fact what it is and it is there intentionally).
That said, please let me know if:
A) I am missing where this can be changed
B) If making the “Untagged” tag capitalization as a preference (“make all tags lowercase” checkbox?) could be added as a feature request?
I’m not aware of any way to change it. As for feature requests, it might be possible to programmatically do it without a new setting – if all the user’s tags are lowercase, make ‘untagged’ lowercase.
If you don’t actually need to review untagged items and you are just bugged by it in the Tags view, here’s a custom perspective that gets you part of the way there:
But I notice it shows tags that have available items. The original tags view will show all your tags, not to mention your beloved ‘Untagged.’