It is true that Fritzing does not like to “start” a wire connection from a connector that already has a wire at it. It wants to pick up the end of the wire, to allow you to move it somewhere else. Here are some tricks / techniques to get the result you want.
- Simplest case. Start the wire from the other end. As long as that currently does not have a wire at it.
- Start the wire from any existing unused pin or connection pad, and end at the pin you were trying to start from. Then move the start of the wire to where you were intending to end it. Or start from that empty pad and drag to where you want the wire to end, then move the start of the wire from the temporary pad to where you really wanted to start it from.
- In the View menu, turn off the “Wires Layer”. With the wires not displayed, they can not be selected, so you actually CAN start wire at a pin that has a (now invisible) wire connected to it. Starting dragging of a wire out from the connection automatically turns the wire layer back on, but by then the wire is already started, to everything works.
Initial layout with just the pair of wires.
Drag wire from other pin (yellow circle here) too the pin with a wire on it.
Draw wire from a temporary pad (again in yellow) to the connection with (now multiple) wires at it.
Move the end of the wire from the temporary pad to where you want it.
Turn off wire layer in the view menu
Drag wire from the pin that has multiple (initially) invisible wires connected