Comment 3 for bug 1836813

Sorry, I tried so hard to make it complete. Doh!

This is the Windows version, Portable.
On Windows 10 64 bit Home
Latest version of Calibre - oops. not quite, new version is out... I'll verify after I get the new version installed but this has always been the functioning for at least the couple of years I've used Calibre.
Yes. It is the "Category editor (Tags)" page - i.e. Tags, Right-click Manage Tags