I have an assembly where two components are imported Rhino models, and I am modeling additional components in it.

In the beginning it was easy, but now it is not possible to select vertices or edges in the model when I edit parts in context in the assembly window. I can only select surfaces. This is true for both the imported components and parts modeled from scratch.

This happens only in shaded view, with or without edges.

If I change view to Hidden lines visible, Hidden lines removed or Wireframe everything is working OK.

If I open a part in a separate window, it's also working OK.

Can the model be too complex? The Rhino parts are fairly complex.