When working with ProStructures elements it is always best to turn on the ProStructres snaps.
Go to ProStructures Options > Snaps.
Set the settings shown below
Now for the snaps you will have three options.
None, default MicroStation snaps (endpoint, intersection etc.)
ProStructures snaps, which will magnet to the points shown here switching between them using the keyboard arrows.
They will magnet to the start and end points and any of the closet points along the length of the object according to the Keypoint Snap setting (enabled with the “K” key).
The other option is to select the Legacy snaps, which will only snap to the centerline of the object along the same dividing point set by the keypoint snap.
We also have in this dialogbox the option to change the tooltips that will appear to us as we hover over an object. We can have the standard MicroStation tooltip, or the customizable ProStructures tool tip.
Lets not forget to also mention the very useful Data Point Keyin (Enabled with the “P” key)