Bug 321755 EPS adds a part without considering its placeholder if no target container or part stacks could be found
The summary probably makes no sense. Will deliver a fix with a test in a bit.
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/PartServiceImpl.java
}
	private void firePartDeactivated(MPart part) {
		for (Object listener : listeners.getListeners()) {
			((IPartListener) listener).partDeactivated(part);
		}
	}
	private void firePartHidden(MPart part) {
		for (Object listener : listeners.getListeners()) {
			((IPartListener) listener).partHidden(part);
		}
	}
	private void firePartVisible(MPart part) {
		for (Object listener : listeners.getListeners()) {
			((IPartListener) listener).partVisible(part);
		}
	}
	private void firePartBroughtToTop(MPart part) {
		for (Object listener : listeners.getListeners()) {
			((IPartListener) listener).partBroughtToTop(part);
		}
	}
	public void addPartListener(IPartListener listener) {
		listeners.add(listener);
	}
	public void removePartListener(IPartListener listener) {
		listeners.remove(listener);
	}
	private MWindow getWindow() {
		return ((MContext) rootContainer).getContext().get(MWindow.class);
	}