JetStream allows you to configure the appearance and selection style of the measure tools and the measurement drawing in the main navigation window.
Go to Tools, Global Options, Measure
The Measure dialog is displayed

Set the Color and Line Thickness of the measure lines.
Check the In 3D check box if you want to draw the measurements in 3D in the main view. They then act as 3D lines in the scene which can be obscured by other geometry. If this box is unchecked, then all measurement lines are drawn in 2D over the top of the all geometry.
Set the measure picking style by checking the Vertex Edge and/or Line End check boxes. The cursor will snap to the nearest vertex, triangle edge or line end respectively, depending on the options chosen.
Set the Snap Tolerance . The smaller the tolerance, the closer the cursor needs to be to a vertex or edge before it snaps to it.
Click OK to set the options or Cancel to exit the dialog without setting them.