function isInOverflow (oElement, oContainer) {
			const oElemRect = oElement.getBoundingClientRect();
			const oContRect = oContainer.getBoundingClientRect();

			return (
			  oElemRect.bottom > oContRect.bottom ||
			  oElemRect.top < oContRect.top ||
			  oElemRect.right > oContRect.right ||
			  oElemRect.left < oContRect.left
			);
		}
Handler for the Collapse all button
@param oEvent