I have been using mobi one for a few months and have worked extensively with select lists in my contract formulation app.
I think the following two improvments would be well received particularly the first.
1. ability for single selection select lists to start with no item selected and also subsequently be deselectable to none selected by re-clicking on the selected item. (this goes for menu select lists too)
2. a way in the design view to make all the items in a list re-size to a uniform height. i.e. list is created, moved, resized. Then new item is added at the standard dimensions and when the whole list is resized the relative difference remains.
As always nit picks in an excellent program that has proven great value for money.