active click-drag selection of ranges in column selection should work in same way as rows

(via email)
Active (dragging) selection issue
• during selection process (dragging) selected sequences can't be deselected
• during selection process (dragging) columns are deselecting properly only if you deselect in the left direction.
If selection was dragged in left direction an thus you start to deselect moving cursor right, instead of deselecting it starts to do new selection.

(intepretation)
Basically, if you start to click and drag to create a sequence selection, dragging below the start point adds sequences in the downward direction and removes them when dragging in the other direction until the selection crosses the start point, and then sequences are added to the selection.

However - when clicking and dragging to the right or left on the alignment ruler, dragging to the left frst and then to the right deselections only occur when the mouse is dragged to the left when it is to the right of the start position.