This is a minor thing but I am taking a video training course and noticed that, in the video training the value displayed in the dimension panel was 2.104m when 2104mm was entered. This is what I would expect to see. In my Blender installation, the displayed value is 2.1m. It appeared to be rounded in the display but if I edit it, it displays correctly as 2.104M.
The video training is using Blender V 2.78 and I am using V 2.79.
Training Video Panel:
My Installation:
My Installation When Editing the Value:


