Currently in IGB a user has 2 options for determining the length of a custom region (I am considering an intron a custom region since you cannot select just the intron by itself):

1. Select exons that sandwich the intron and view selection info to view the Start and End positions. Then, using math, you can subtract an ending position form a starting position. (This way is fastest, but still not that fast).
2. You can zoom in to the precise base you want to start at and click-drag along the sequence axis to select a contiguous sequence, but the problem is that your selection is finished once you pick up your mouse click, therefore you have to remain at the same zoom level and just wait for the view to scroll horizontally until you have reached your ending location. (Can be very slow depending on the length of your custom region).

Ideas for improvements:

*Add a "Toggle Length" function to the toolbar or somewhere that a user could click to display the lengths of exons and introns above each individual exon and intron. This would allow a user to quickly see lengths for ALL introns and exons, not just one they are curious about.

*Add a function to the context menu of the sequence or coordinates axis in which you could "Set point 1" and then zoom to a different area of interest and "Set Point 2". Then you could display selection info (length) for the region selected between the Set Points. This would allow a user to quickly determine the size of ANY custom region.

*Allow for selection of individual introns. This may be a large implementation, but I do believe that it would enhance the user experience in IGB.

There is, in fact, at least a slight user demand for this improvement that we are aware of, documented in IGBF-215. I am confident that other users would also appreciate this enhancement.