Bug 318944 CSSSWTEngineImpl leaks memory
CSSSWTEngineImpl stores too many element contexts. In a memory snapshot, the HashMap size was 15559. This is most probably a leak.
bundles/org.eclipse.e4.ui.css.core/src/org/eclipse/e4/ui/css/core/impl/engine/AbstractCSSEngine.java
public CSSElementContext getCSSElementContext(Object element) {
		Object o = getNativeWidget(element);
		return (CSSElementContext) getElementsContext().get(o);
	}
	public Object getNativeWidget(Object element) {
		Object o = element;
		if (element instanceof CSSStylableElement) {
			o = ((CSSStylableElement) o).getNativeWidget();
		}
		return o;
	}
	protected Map getElementsContext() {
		if (elementsContext == null)
			elementsContext = new HashMap();
		return elementsContext;
	}
	
	/**
	 * Handle exceptions thrown while parsing, applying styles. By default this
	 * method call CSS Error Handler if it is initialized.
	 * 
	 */
	public void handleExceptions(Exception e) {
		if (errorHandler != null)
			errorHandler.error(e);
	}
	public CSSErrorHandler getErrorHandler() {
		return errorHandler;
	}
	/**