When using a plugin that implements IRenderWindowPartListener (e.g. in QmitkSegmentationView, QmitkPropertyTreeView), the overridden function RenderWindowPartActivated is not called. This is due to the fact that the Display with the StdMultiWidgetEditor (the current render window part) was visible and activated before. So no signal is emitted, when the plugin is opened. However, the signal is emitted when the display is hidden and then shown again, e.g. by opening and closing the DICOM Browser.

Therefore the m_SlicesInterpolator of the segmentation-plugin is not initialized with the tool manager. Using an invalid tool manager leads to a crash when trying to interpolate between segmentation slices.

I propose to look into the different implementations of the plugins and check, if the code is initialization code that can be moved to the constructor or to the Activated/Deactivated-functions (which may be called also during plugin lifetime). If the code is RenderWindowPart-dependent code, like getting the render windows, we have to think of another solution.