In a model if you sketch a rectangle then apply a dimension to a line normally the dimension will show up and you drag it to where you want to place it. Well this has happened to me before where you can not dimension a line and get the dimension to show up unless you select a point on the screen then it appears, and you don't get the window to pop up that allows you to input your own dimensions for the line either. You end up selecting line 1 then line 2 then a place to drop the dimension; pow it shows up.
If I remember correctly this is a check box in one of the properties. Anyone know where that is?