I have played around with the PostGIS connections and I have found it a bit confusing. I supposed it is due to the way it is meant to integrate with the QGIS DB Manager.
I coundn't edit the PostGIS connection characteristics that I had just created except for the user and password (or no hint to do hint through another of the QGIS dialogs).
I couldn't delete the connection
I ended up editing it through the 'Add PostGIS Layers'
But then the OpenGeo explored connection lists and the 'Add PostGIS Layers' connection lists went out of sync when I renamed one through the 'Add PostGIS layers' dialog.
add a new option to add a new connection from the explorer
try to see if a signal is emmited when the list of db connections is modified, and update the explorer tree (this is done already when layers are updated)
I have played around with the PostGIS connections and I have found it a bit confusing. I supposed it is due to the way it is meant to integrate with the QGIS DB Manager.