Like a video editor. I've been wanting that for a long time. I think that's what the time entry windows at the bottom of the work window do.
If there is going to be a tool like this it's much more likely to be in Audacity 1.3 and not 1.2.
Audacity 1.2 is very old and no longer supported,
patched, corrected, or updated. Audacity 1.2 can
be unstable on newer computers.
Download and install the latest Audacity 1.3 from here...
http://audacityteam.org/download/
You can install both audacity 1.2 and Audacity 1.3 on
the same computer, but only use one at a time.
Audacity 1.2 will not open projects made on Audacity 1.3.
If you use MP3 or some of the more modern audio
compression formats, get Lame and FFMpeg software
from the same web site. Do not use older software
or software from other web sites, even though they
may have the same names.
Dig around in this...
http://manual.audacityteam.org/man/Audacity_Selection
Koz