Embedded 2D content in 3D scene blocks selection in 3D edit window

If there is an embedded 2D item in a 3D scene, it will block picking across its whole plane (not just the visible size). Optimally it should pick the 2D item correctly when the pick ray intersects it, but in current version 2D items will not usually be visible in 3D editor, so for now, 2D item should just be ignored when picking.