If Pointer Size is set to Full View under Preferences, cross hairs will disappear when placing first point of Dimension, but reappear after placing second point.
Problem is caused if using old legacy tools such as Dimension Size with Arrow.
If using Dimension Linear tool from Main tool bar, problem does not occur. It is believed this is because, with the old legacy tools, there are no dynamics between the first and second data point. Problem seems to be resolved in XM, regardless of whether legacy or new Dimension tools are used.