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.swt/src/org/eclipse/e4/ui/css/swt/engine/CSSSWTEngineImpl.java
super.registerCSSPropertyHandler(CSSPropertySimpleSWTHandler.class,
				CSSPropertySimpleSWTHandler.INSTANCE);
		
		super.registerCSSProperty("maximize-visible", CSSPropertyMaximizeVisibleSWTHandler.class);  
		super.registerCSSPropertyHandler(CSSPropertyMaximizeVisibleSWTHandler.class,
				CSSPropertyMaximizeVisibleSWTHandler.INSTANCE);
		
		super.registerCSSProperty("minimize-visible", CSSPropertyMinimizeVisibleSWTHandler.class);  
		super.registerCSSPropertyHandler(CSSPropertyMinimizeVisibleSWTHandler.class,
				CSSPropertyMinimizeVisibleSWTHandler.INSTANCE);
		
		super.registerCSSProperty("mru-visible", CSSPropertyMruVisibleSWTHandler.class);  
		super.registerCSSPropertyHandler(CSSPropertyMruVisibleSWTHandler.class,
				CSSPropertyMruVisibleSWTHandler.INSTANCE);
		
		super.registerCSSProperty("maximized", CSSPropertyMaximizedSWTHandler.class);  
		super.registerCSSPropertyHandler(CSSPropertyMaximizedSWTHandler.class,
				CSSPropertyMaximizedSWTHandler.INSTANCE);
		
		super.registerCSSProperty("minimized", CSSPropertyMinimizedSWTHandler.class);  
		super.registerCSSPropertyHandler(CSSPropertyMinimizedSWTHandler.class,
				CSSPropertyMinimizedSWTHandler.INSTANCE);
		
		super.registerCSSProperty("single", CSSPropertySingleSWTHandler.class);  
		super.registerCSSPropertyHandler(CSSPropertySingleSWTHandler.class,
				CSSPropertySingleSWTHandler.INSTANCE);
		
		super.registerCSSProperty("unselected-close-visible", CSSPropertyUnselectedCloseVisibleSWTHandler.class);  
		super.registerCSSPropertyHandler(CSSPropertyUnselectedCloseVisibleSWTHandler.class,
				CSSPropertyUnselectedCloseVisibleSWTHandler.INSTANCE);