Can't edit mp3 selection

Hi,

I have started using Audacity in order to make some loops from mp3’s. But I’m having trouble trimming to my selection. I am trying to follow this online tutorial:

http://www.maclife.com/article/howtos/build_your_own_garageband_loops_any_music_file

The problem is i do the following:

• import mp3
• select the area i wish to keep
• play in looped mode by using shift

• try to trim to selection but can’t as the trim field in the edit menu is greyed out as follows

any thought on what i’m doing wrong would be much appreciated.

edit: using os 10.6.8 and installed audacity from the dmg

You need to be in Stop mode, not Play or Pause for any of Audacity’s editing functions to work.

– bill

Thanks so much…works now.