Command: Show Insert Positions
Shortcut: Ctrl+Shift+M
Call: Ladder menu
All insert positions are displayed in the active network.
In the ladder diagram, possible insert positions are marked by symbols. The symbol indicates how the inserted element is connected to the existing network.
Rectangle:
Insert position to the right of elements which have already been inserted
Rhombus:
Insert position to the left of elements which have already been inserted
Triangle:
, 
Insert position after a branch on a parallel connection which runs down (triangle points downwards) or up (triangle points upwards).