Old tag name to appear in new name field of rename dialog

When renaming tags, the field for new name is empty. It's useful for replacing tags with others, but if I just want to change few characters in tag name or add/remove parent, I have to re-type or copy-paste old name into "new name" field manually. I guess it should look like renaming of files and folders in windows: old name appears selected, so if user begins typing, old name disappears.