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
if (element instanceof CSSStylableElement) {
			CSSStylableElement stylableElement = (CSSStylableElement) element;
			return stylableElement.getStaticPseudoInstances();
		}
		return null;
	}
	/**
	 * Callback method called when styles applied of <code>nodes</code>
	 * children of the <code>element</code>.
	 * 
	 * @param element
	 * @param nodes
	 */
	protected void onStylesAppliedToChildNodes(Element element, NodeList nodes) {
		if (element instanceof CSSStylableElement)
			((CSSStylableElement) element).onStylesApplied(nodes);
	}
	
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.e4.ui.core.css.engine.CSSEngine#applyStyleDeclaration(java.lang.Object,
	 *      org.w3c.dom.css.CSSStyleDeclaration, java.lang.String)
	 */
	public void applyStyleDeclaration(Object element,
			CSSStyleDeclaration style, String pseudo) {
		
		currentCSSPropertiesApplyed.clear();
		List handlers2 = null;
		for (int i = 0; i < style.getLength(); i++) {