Hi Brian, it looks like a bug, I'll take a look at fixing it up. It looks like it is related to a couple of surfaces inside the solid that may have a problem with their trim curves.

In the meantime a quick workaround is to use the alternate style window select, where you start the selection window on the upper-right corner of the area to select and move towards the left with your mouse, rather than moving from left to right.

That will do the "crossing" selection style that targets any object that is even partially within the window, rather than only fully contained ones like the left-to-right method.

The crossing window will be able to grab your shape in this case.

- Michael