* actual behaviour: code which can be called from menu or toolbar actions has to be located inside CoreUI, because the menu and toolbar is created inside CoreUI/Bundles/org.mitk.gui.qt.application
* expected behaviour: it should be possible to add actions specific to the ExtApp (for example) and hence a dependency on non-Core code is needed
== Cause of the bug ==
This "feature" was not neede before and hence the code has not been designed for this use-case.
== Proposed solution ==
Introduce a new org.mitk.gui.qt.extapplication bundle in mitk/Modules/Bundles which has its own IApplication and WorkbenchAdvisor implementations. When it makes sense, derive the classes from org.mitk.gui.qt.application.
== Affected classes ==
The WorkbenchAdvisor and similar classes in org.mitk.gui.qt.application will be made public and some code will be moved to a non-Core directory.