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
newValue = converter.convert(value, this, context);
				if (newValue != null) {
					
					if (resourcesRegistry != null) {
						if (key != null)
							resourcesRegistry.registerResource(toType, key,
									newValue);
					}
				}
			}
		}
		return newValue;
	}
	public String convert(Object value, Object toType, Object context)
			throws Exception {
		if (value == null)
			return null;
		ICSSValueConverter converter = getCSSValueConverter(toType);
		if (converter != null) {
			return converter.convert(value, this, context);
		}
		return null;
	}
	
	/**
	 * Return instance of CSS Parser.
	 */
	public abstract CSSParser makeCSSParser();
}