This is possible to do, but - depending on your drawing type - you may want
to avoid the practice. Go to Tools > Snap & Glue to enable glue to
geometry. This should enable the connections. If you are making a drawing
where you expect the connectors to automatic reroute and stay glued to one
another, you should stick with a more conventional "1-D lines glued to 2-D
objects" arrangement. I think you will be happier with the results.