Description:

In a multitrack environment, after applying an effect on a track (or part of it), its controls in the mixer panel became uneffective (the "Mute" and the "Solo" buttons and the sliders won't produce any effect). The controls of the other tracks works correctly. The only way to get through is to save the project, close Audacity, restart it and load the project again.
When the problem occurs, sometimes Audacity freeze while playing (the entire UI freezes while the audio output continue to play) if I use the panel mixer on the "locked" track.

Additional info:
* package version

audacity 1.3.13-1

x86_64 (I didn't try with the 32bit version)

Steps to reproduce:

open Audacity
create a project with more than one track
open the panel mixer
apply an effect to one of the tracks (or part of it)
start playback
on the panel mixer press the "Mute" or the "Solo" button or move the slides of the edited track