Inventor assembly rotate view center of rotation

I typically work with "long" assemblies (on the order of 12" x 36" x 1500") with several component parts and sub-assemblies along length. I will often need to be able to rotate all around and zoom in and out in a small area along length. I can do this by opening the view steering wheel and locking the center to some point of geometry around which I want to rotate. The problem is that oftentimes the center "disappears". I think it happens when I place a new component or tab to a different file. When I try to rotate it either spins about the CoG of the main assembly or around some point way out in outer space. Is there some setting I can toggle to have Inventor rotate about the center of what is displayed on my monitor and ignore the very long lengths going off screen to each side? Or is there a way to "lock" the center of rotation until I want to turn it off?

I don't know about a "locking" but while in the Free Orbit command if you do a long left click within the arcball - the center of rotation should move to where you do the long left click.

So, while in Orbit - hold mouse wheel to pan to where you want to work and then long left click to set desired center of orbit.

Awesomesauce! Inventor has done this behavior in the past "accidentally", I must have inadvertently done a long click. I just did some experimenting and this is exactly what I'm looking for. F4 and long left click, release and screen "re-zeros", future F4 and rotation will be about selected point. So previously when my model was rotating about a point outside the model I must have done a long click out in la-la land to confuse it. Thanks JD!