Gets a value that declares whether the per-pixel opacity of the source window content is respected.
Assembly: PresentationCore (in PresentationCore.dll)
By enabling per-pixel opacity, the system no longer draws the non-client area.
The opacity is used when the window is drawn on the desktop (it represents a final rendering step and does not appear as a contributor to property values such as Opacity).
applies only to top-level windows.
Available since 3.0