The example is the one I e-mailed you about in the Summer where someone was recording ultrasonic vocalizations produced by animals. The vocalisations would never be shorter than a given length but could be fairly loud. He has lots of short (often loud) noises in the recording that cannot be animal noises and wanted a way to remove them from the analysis. This can’t be done currently unless the noises are below the silence threshold.
Someone else suggested such a feature afterwards but did not give a use case.
Rather than allow only one control or the other to work, I assume the “ignore” takes precedence and the “sound” starts at 1.2s.
There was an updated version http://forum.audacityteam.org/download/file.php?id=2122 discussed in this thread that puts the negative sign in the text box. I had forgotten that, but that’s fine.
Can’t find any evidence of a “behind zero” fix - if a sound is behind zero its label is behind zero in the above id2122 version.
Gale