Drop-down list of existing entries when renaming the tag [feature-request]

andselisk

I think it would be nice to have a list of already existing tags to appear as one starts typing in the text field when renaming the tag. I noticed that I have several slightly different tags starting similarly, and basically meaning the same, so now I have to merge them by hand. This would've never happened if a list of already existing tags would've been shown when one does the tag editing.