While in Concept Mode, when switching between Metric and Imperial units, the program behaviour was inconsistent and unpredictable. Sometimes the grid co-ordinates for the new unit system would appear on the screen, but the previous unit system would still be in the Format settings when you returned to them. At other times, the co-ordinates for the new unit system would not appear on the screen. This has been corrected and the new unit system immediately appears, and is in the Format settings when you return to them.
Note that other Format settings that affect Concept Mode, like Diagram Font Size, also exhibit this behaviour.