In adjusting and lining up a track with other, I used the moving clip function towards the left. Than 2 little arrows pointing to the left side are visible.
Lets say I moved 1 sec duration off to the left. The visible total length of the track is for example 1 minute.
If I export ALL tracks as a complete MIX than the length is 1 Minute.
The track which has been moved towards the left by 1 sec. and exported separately has a total length of 1.01 Minute!
Every track, which has been moved to the left and has 2 arrows indicators, will add the section no longer visible to the total length when exported as selected track.
At least there should be a option for those tracks given the real length or the visible length of duration, in case that this behavior was intended.
That is correct behaviour (If I understand your post correctly, you are happy with this part).
That behaviour depends on exactly how you are doing it.
If you are using “Export Selected Audio”, then whatever audio is selected will be exported.
If you select the entire track (including the region before zero) then the entire track (including the region before zero) will be exported.
If you select from time=0 to the end of the track, then only the selection from time=0 is exported.
In previous versions of Audacity, you could see in the TimeLine (the ruler at the top) if the selection extended before zero. (See image below). Unfortunately the selection is no longer shown in the TimeLine (see: https://github.com/audacity/audacity/issues/2067)