Q: Can't 'detect tempo' under audio drop down menu :-(

Hi

I am trying to fix up the tempo to quantisize a track and I can't seem to be able to use 'detect tempo' under the audio drop down menu. 

When I select the region and then click on 'detect tempo' I am told that there are 'no regions selected'.

I selected the regions in both the main window and in piano bar seperately but still no luck.

Any help would be fantastic!

Thanks soo much!

Cinta