A re-init of the data nodes occurs often during a workflow. The mxn multi widget has some problems with that.
In a typical scenario the user opens a specific number of render windows, shows / hide certain data nodes of the storage to individually display different images. Maybe navigate individually in each render window (zoom, scroll).
If a reinit for all registered render windows is requested, this user defined preset will be reset to the node being reinitialized.
I propose to first gather different actions which lead to a update request.
**Multi Widget (Editor)**
- changing the preferences page of the std- / mxn- multiwidgeteditor
- creating a new segmentation via the segmentation view
- changing the node selection in the data manager, if auto selection is enabled
- if the contour marker is selected
- changing the preferences page of the segmentation view
- allow //locking// specific render windows
- use own rendering manager for the mxn multi widget (not the singleton one) so that the `mitk::RenderingManager::GetInstance()->RequestUpdateAll()` or `GetRenderingManager()->RequestUpdateAll()` calls do not affect the render windows of the mxn multi widget
- only initialize certain render windows (active / selected, related to used node, ...)