Each track currently can show up to four track icons:
1. lock (locked/unlocked)
2. speaker (muted/unmuted)
3. film (video enabled/disabled)
4. "box" (composite/opaque)

While track icons 1, 3, and 4 are b/w only, the speaker icon instead changes its color. To me, the color red doesn't convey a clear meaning: does this mean that this track has audio? Surely that's not the intended meaning, but that is what I was thinking when I first saw a red speaker icon.

A consistent scheme would be to cross out the speaker icon #2 in the same way as it is done with the film strip icon #3. In the same way the color change should be removed, or alternatively, all icons #1, #2, and #3 should conform to the same color change indication.

Reproducible: Always

Steps to Reproduce:
1. Create new Kdenlive project.
2. Click on the speaker icon on the topmost track.
3. Click on the film strip icon on the topmost track.

Actual Results:  
Speaker icon becomes red but still shows a speaker emitting sound. The film strip becomes crossed out.

Expected Results:  
Speaker icon becomes crossed out as does the film strip icon.