This image from IGB 6.7 demonstrates track operation "A not B" that creates a new track containing annotated regions present in A but absent from B. An "A not B" track can highlight differences between runs of the same analysis software using different parameters, new additions to an annotated gene set, and even differential expression across RNA-Seq data sets.
Here, the "A not B" track occupies the top row of the IGB display.
