This is a sample Form which shows you how to have one List (say item no.) on the left, and another list (actually a sub form) with say description and other fields on the right.
Conceptually similar to how it was done in the DOS version of Navision, or like Freeze columns in Excel.
NOTE: the scroll wheel on a mouse will cause issues, and also the two lists must have the same number of rows. SO if there is a horizontal scroll bar in one and not the other it wont work.
This form (as it is) will not work in full screen, but is easy to modify so that it will.
The objects are very old (Navision 1.30) but work in all version of NAV.