# Source (filter, event)

A Source component is a filter, used for drag-and-drop actions. It generates an event on an uncancelled upclick. A typical event-handler will then inquire the `ActiveTarget` property to determine whether the Source is over a Target and take some action if it is. For example, a source-icon representing a file might delete the file when it is dragged and released over a target-icon representing a ``trash can.'' A tiling window manager might make every window both a Source and Target to permit windows to be exchanged.

ActiveTarget `G`
  (Text) The name of the component over which the Source is located. This property is ignored when the Source is defined; it only has a value while the callback associated with the Source is active. The call to `FormsVBT.GetTextProperty` raises an `Error` exception if the Source is not over a valid Target on an uncancelled upclick or if the Target does not have a name.

Behavior
  If the Source is located over a Target when the mouse-button is down, the Source's `hit` method is called.
See Also
  Target