When searching start at selected not current event. Closes #1030
When searching start at selected not current event. Closes #1030

* When selecting a marker region, the more intuitive search is to find children
  of the marker first before searching onwards, even if the 'current event' is
  at the end of the marker region.
TurtleRockStudios/renderdoc_public,Zorro666/renderdoc,Zorro666/renderdoc,baldurk/renderdoc,Zorro666/renderdoc,baldurk/renderdoc,TurtleRockStudios/renderdoc_public,baldurk/renderdoc,Zorro666/renderdoc,baldurk/renderdoc,Zorro666/renderdoc,googlestadia/renderdoc,googlestadia/renderdoc,googlestadia/renderdoc,Zorro666/renderdoc,googlestadia/renderdoc,baldurk/renderdoc,TurtleRockStudios/renderdoc_public,googlestadia/renderdoc,TurtleRockStudios/renderdoc_public,googlestadia/renderdoc,TurtleRockStudios/renderdoc_public,TurtleRockStudios/renderdoc_public,baldurk/renderdoc