Bug 314685 EModelService's findElements(MUIElement, String, Class<T>, List<String>) method can return duplicates
I'm getting two editors in the returned list that's pointing at the same thing. The returned collection is a List and not a Set but this feels wrong.
bundles/org.eclipse.e4.ui.workbench/src/org/eclipse/e4/workbench/ui/internal/ModelServiceImpl.java
}
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.e4.workbench.modeling.EModelService#swap(org.eclipse.e4.ui.model.application.
	 * MUIElement, org.eclipse.e4.ui.model.application.MPlaceholder)
	 */
	public void swap(MPlaceholder placeholder) {
		MUIElement element = placeholder.getRef();
		MElementContainer<MUIElement> elementParent = element.getParent();
		int elementIndex = elementParent.getChildren().indexOf(element);
		MElementContainer<MUIElement> phParent = placeholder.getParent();
		int phIndex = phParent.getChildren().indexOf(placeholder);
		
		elementParent.getChildren().remove(element);
		phParent.getChildren().remove(placeholder);
		
		boolean onTop = element.isOnTop();
		boolean vis = element.isVisible();
		boolean tbr = element.isToBeRendered();
		element.setOnTop(placeholder.isOnTop());
		element.setVisible(placeholder.isVisible());
		element.setToBeRendered(placeholder.isToBeRendered());
		placeholder.setOnTop(onTop);
		placeholder.setVisible(vis);
		placeholder.setToBeRendered(tbr);
		
		elementParent.getChildren().add(elementIndex, placeholder);