BUG: Sometimes I cannot drag the map.

On several occasions I try to reposition the map by clicking and dragging, but it gets locked up. This has happened on several computers, using the last few versions of MP including the latest beta. As a work around, I need to change to the Flight data screen and back again.

Start by reproducing the map drag lockup on the affected computers and recent Mission Planner versions, then compare behavior before and after switching to the Flight data screen and back. Trace the map interaction entry point once the failure is reproducible. Done means the map can be repositioned reliably without using that workaround.

Written by the indexing model from the issue text.