Currently, 3D features such as Extrude or Split do not allow for choosing invisible or unshared sketches directly from the Model Tree. You have to first enable Visibility or Share the sketch, then open up the 3D feature and select the sketch.
In many cases this seems like an unnecessary step. I therefore propose that selecting an consumed+invisible sketch from the Model Tree automatically Shares the sketch, similar to when you select a consumed but Visible sketch.
The same should apply for consumed+invisible surfaces.
Please disregard of the atrociousness of the exemplary CAD work down below.
