TSRichViewEdit.OnRVDblClick

Occurs when user double-clicks the primary mouse button when the mouse pointer is above the item in RichView (or on single left-click, if rvsSingleClick is in RichViewEdit.Options)

property OnRVDblClick: TRVDblClickEvent;

See the event of the same name in the RichView help file (event of TCustomRichView).