The mxn multi widget does not show the level-window slider. This is because
- with multiple topmost visible data nodes it is not easy to decide which data node the level-window slider should manipulate
- with the PACS mode always active (BlackSwan context) the mouse can be used to change the level-window inside a render window
However, with T26490 and T26492 it is now required and possible to show the level-window slider and manipulate the topmost visible data node inside the currently active render window.
Showing the level-window slider enables the use of the presets.