It is too hard to enter a Tag that is a strict subset of an existing one

(Incomplete Feature, Investigate , Priority: Medium, Test Status: No automated tests yet , Reported By Justin du Coeur, )

Editor

Summary: For example, say that there is an existing Thing named "Footer", and I want to create a Tag named "Foo". There is no obvious way to do it -- it prompts me with "Footer", and doesn't give me the option of creating the new one. The workaround is very unobvious: I have to click away from the control, which causes it to accept what I have typed.

Is it even possible to do this right with OOTB Manifest? The right UI is probably to show what I am typing as the top element in the list of options (or at least, as the bottom one), so that I have something I can accept. I may have to enhance Manifest to get this, I suspect.