View -> Select Lines

With this tool, you can show all connections (lines) that lead to or away from a selected block in color.

If you select a single connection configured with this function, LOGO!Soft Comfort highlight the selected connection in color.

Also, if you select a block configured with this function, LOGO!Soft Comfort show the reference block of the selected block with its frame in red.

Under Tools > Options: Preference you can set whether to label the connections or not. Under Tools > Options: Colors you can set the colors to use to display the connections.