You try to connect to shapes via a connector on a diagram. Shapes cannot be connected although glues points are available on shapes.
The problem is that GLUE is turned off for the diagram, i.e. Visio saves glue settings in the diagram file; for this particular diagram they are turned off, and the diagram is saved in this state. Turning glue off results in this behavior, connectors cannot be glued to shapes.
You have to turn the glue back on (button “Toggle Glue” on toolbar “Snap and Glue” (or key F9).
- Activate the toolbar “Snap and Glue”.
In Visio 2010:
Select “More Commands…”
Choose commands Not in the Ribbon
Select command ”Toggle Glue” (”Klebepunkte ein/aus” in German) and click on Add.
- Make sure that the item “Enable glue” is checked.