You can simultaneously show and select a connection.
Click on the connection.
...
1. Select an object.
2. Activate the Relationships tab.
3. Click on the row containing the connection.
4. Click on the Display button.
The connection is selected.
■ If an occurrence of the connection already exists in the model, that occurrence will be selected.
■ If no occurrence of the connection exists in the model yet, the connection is shown and selected together with the object occurrence to which it is connected in addition to the selected object.
You deleted object occurrence B, which was connected to object occurrence A. Therefore, you also deleted connection occurrence K between the two object occurrences. If you click on object occurrence A, select object B on the Relationships tab page and click on the Show button, an object occurrence B and an occurrence of connection K will be created. The connection will be selected.