To disconnect objects in the Inspector
To disconnect objects in the outline mode:
Click the right-pointing triangle to see connections into this object. Click the left-pointing triangle to see connections from this object.
As you hold down the Control key, the cursor turns into a scissors. If it doesn't, make sure the cursor is in the column that contains the connections' names and icons. If you Control-click on the left side of the column, the click begins a connection operation.