(CTRL+SHIFT+left mouse click used to work, but does not seem to work any longer with the Dual Engine edition)
Content Creation Bugs Editions Composer 3D Scene Editing Unreal
It is not possible to move objects by "CTRL+SHIFT+left" that are rendered by the Unreal Engine.
You can move billboards at their Control Board's transformation:
(or in the preview window if Edit Scene on turned on)
Also, you can edit the objects in Unreal Editor while the level is running, if you are using Live Sync connection mode.