I used to benefit from the multiple label track functionality that Audacity had,
but it seems to be dismissed in the latest beta (1.3.4b). In turn, the user can
only put their labels in one track by calling the "add . I wonder what specific
consideration has been placed on this issue.

My previous hack on Audacity's behavior was meant to reduce the amount of
work on typing when labeling by:
  1. Assign a title to the label track to label just one concept such as "guitar solo"
  2. Label the related guitar solo section of the music without manually typing in anything for each label.
  3. Then export the labels, before which, the labels are automatically tagged with the label-track title.
To label an audio stream with multiple concepts, with the above way I can create multiple parallel label tracks that deal with different concepts, minimizing my work of typing.

If there are better ways to achieve my goal, could anybody explain to me?