Bug 320142 Editors no longer activate when clicking on their tabs
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/ui/internal/workbench/ModelServiceImpl.java
MUIElement insertRoot = relTo.getParent();
		while (insertRoot != null && !(insertRoot instanceof MWindow)
				&& !(insertRoot instanceof MPartSashContainer)) {
			relTo = (MPartSashContainerElement) insertRoot;
			insertRoot = insertRoot.getParent();
		}
		if (insertRoot instanceof MWindow) {
			
			MPartSashContainer newSash = BasicFactoryImpl.eINSTANCE.createPartSashContainer();
			newSash.setHorizontal(where == LEFT_OF || where == RIGHT_OF);
			combine(toInsert, relTo, newSash, newFirst, ratio);
		} else if (insertRoot instanceof MGenericTile<?>) {
			MGenericTile<MUIElement> curTile = (MGenericTile<MUIElement>) insertRoot;
			
			if (curTile.isHorizontal() && (where == ABOVE || where == BELOW)) {
				MPartSashContainer newSash = BasicFactoryImpl.eINSTANCE.createPartSashContainer();
				newSash.setHorizontal(false);
				newSash.setContainerData(relTo.getContainerData());
				combine(toInsert, relTo, newSash, newFirst, ratio);
			} else if (!curTile.isHorizontal() && (where == LEFT_OF || where == RIGHT_OF)) {
				MPartSashContainer newSash = BasicFactoryImpl.eINSTANCE.createPartSashContainer();
				newSash.setHorizontal(true);
				newSash.setContainerData(relTo.getContainerData());
				combine(toInsert, relTo, newSash, newFirst, ratio);
			} else {
				
				int relToIndex = relTo.getParent().getChildren().indexOf(relTo);
				if (newFirst) {