Dimension oddity

On my Windows 7 laptop I get a very odd thing happening every time I create a new drawing.

My units, templates etc are set to mm, yet when I place the first dimension it shows as metres (so 100mm on the dimension displays as 0.1). When I go into the Options>Units and change the radio button to metres, then back to mm, the 0.1 dimension is now 100, and all newly placed dims are mm.

Anybody else come across this?

Windows 7, SolidWorks 2010 SP2

SolidworksUser Interface