regionChanged

Set a callback function for region changes.
[event] regionChanged([in] LONG regionHandle)
This event will be called when the user moves or resizes a highlighted region.

The event will be called with one argument, region, which is the handle for the changed region.

VB6:
Private Sub viewer_regionChanged(ByVal regionHandle As Long) ' a region has been resized ... End Sub
regionSelected
regionDoubleClick