am c70b644: Merge change 1463 into donut

Merge commit 'c70b64441029b9748eea7f260f1b3521dc58eb91'

* commit 'c70b64441029b9748eea7f260f1b3521dc58eb91':
  Fixes #1846038. DrawableContainer was wrongly returning its opacity by ignoring the visibility of the currently selected layer. This change simply reports a TRANSPARENT opacity if there is no currently selected layer of if the selected layer is not visible. Otherwise it reports the opacity computed by the state class.