When you attach more than one hyperlink to an element’s properties, the current one is marked with an icon in the Hyperlinks dialog.
When you use the tools in the Hyperlinks dialog (Browse, Open, Delete), they apply to the currently selected hyperlink. Also, when you select the Open Current Hyperlink tool from the Hyperlinks flyout, it opens the currently selected hyperlink.
To make a specific hyperlink current in the Hyperlinks dialog, just click on any of its fields.