why pencil and brush lines become un-selectable in camera view?

anyone know why a brush or pencil line would suddenly become UN-selectable, neither with ‘select’ tool nor ‘contour editor’, in the camera view, while remaining selectable in the drawing view?
i can duplicate the original layer and the new layer allows selection. is the original layer accidentally getting converted to something unselectable, somehow?
is this a bug?

Can you select it on the camera view by pressing CTRL + click?

can’t seem to; i’m not remembering what control + click usu does in the camera or drawing view. what function would you use that combo for?
and are you thinking this is with the selection or editor tool selected?

There’s an option for the Select Tool that will prevent you from selecting lines from a drawing other than the one active.

https://www.dropbox.com/s/i6mpstrhb0bubfm/selectOption.jpg?dl=1

yea, i know that tool; something else is going on.
i can even solo the problem layer and am still unable to select anything on the layer, or sub layers with the sub layer button on.
also, with the ‘select by color’ red arrow selected, i can select any colors on any layer except for the problem layer.
and extra buggy that i CAN select it in the drawing view.

thanks for your input.