The context fixture is the last fixture which was selected. This fixture is used to determine which attribute controls are displayed to the user.
Namespace: Playbacks.Editor.Selection
ActionScript.SetProperty(Playbacks.Editor.Selection.ContextFixtureHandle,[value])
http://[ip]:4430/titan/get/2/Playbacks/Editor/Selection/ContextFixtureHandle
POST /titan/set/2/Playbacks/Editor/Selection/ContextFixtureHandle