Visual bases checks if visual already staged before adding to stage

Visual bases checks if visual already staged before adding to stage

Fixes bug in which a stage visual can be staged again, caused a new renderer to be created and lost the handle to prevous renderer.
  Meant stray renderers could exist in the control. Leak!

Visual bases checks if visual already staged before adding to stage Fixes bug in which a staged visual can be staged again, caused a new renderer to be created and lost the handle to previous renderer. Meant stray a renderer could exist in the control. Leak! Can occur in control development or with direct use of Visual::SetOnStage. Control Example. Button:Setup { register visual A register visual B } Button::OnStageConnection { enable visual A (call 1) enable visual B Control::OnStageConnection; (call 2) } Call 1 initializes a renderer and puts it on stage. Call 2 initializes and puts on stage all registered visuals without checking if already staged.

Logging in control increased

Change-Id: I98383cac66e833b13765d8aef88767a3e09946b2