Ton Jense 9/26/2012 2:21:06 PM
A matrix of checkboxes would solve only part of the problem.
Another way could be to show two lists; one with the unselected options and a second one with the options already selected. In between the two lists, there are four buttons to
- select one,
- select all,
- deselect one,
- deselect all
I think this solution would be complete foolproof, but much harder to realize.......