Bug 63389 [projection] Do we need a folding region for the top-level type?
The Java editor is currently defining a folding region for the top-level type. I couldn't find a good use of this folding region and in particular it leads to some visual instability when hovering in the vertical rule in between methods. Therefore I suggest to not add this folding region.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/folding/DefaultJavaFoldingStructureProvider.java
/**
	 * Collapses all annotations matched by the passed filter.
	 * 
	 * @param filter the filter to use to select which annotations to collapse
	 * @since 3.2
	 */
	private void collapseMatches(Filter filter) {
		if (!isInstalled())
			return;
		ProjectionAnnotationModel model= (ProjectionAnnotationModel) fEditor.getAdapter(ProjectionAnnotationModel.class);
		if (model == null)
			return;
		
		List modified= new ArrayList();
		Iterator iter= model.getAnnotationIterator();
		while (iter.hasNext()) {
			Object annotation= iter.next();
			if (annotation instanceof JavaProjectionAnnotation) {
				JavaProjectionAnnotation java= (JavaProjectionAnnotation) annotation;
				
				if (filter.match(java))
					modified.add(java);
				
			}
		}
		
		model.modifyAnnotations(null, null, (Annotation[]) modified.toArray(new Annotation[modified.size()]));
	}
}