Tempo detection confusion

Hi all. Just got Cubase 9 Pro installed (W10) as a much needed update to my creaky but familiar Cubase 5. Anyway, I’ve not really had to use any tempo detection before but now I am and I’m having trouble analysing tempo on imported drum stems. I select the track, then project/tempo detection and then ‘analyse’ It goes through the process, then nothing happens. No tempo or sig track created at all. I’ve tried using the kick track and room track. No joy at all.

So what dumb thing am I doing wrong here?