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
/**
	 * Computes the projection ranges for a given <code>IJavaElement</code>.
	 * More than one range may be returned if the element has a leading comment
	 * which gets folded separately. If there are no foldable regions,
	 * <code>null</code> is returned.
	 *
	 * @param element the java element that can be folded
	 * @return the regions to be folded, or <code>null</code> if there are
	 *         none
	 */
	private IRegion[] computeProjectionRanges(IJavaElement element) {
		try {
			if (element instanceof ISourceReference) {
				ISourceReference reference= (ISourceReference) element;
				ISourceRange range= reference.getSourceRange();
				String contents= reference.getSource();
				if (contents == null)
					return null;
				List regions= new ArrayList();
				if (fFirstType == null && element instanceof IType) {
					fFirstType= (IType) element;
					IRegion headerComment= computeHeaderComment(fFirstType);
					if (headerComment != null) {
						regions.add(headerComment);
						fHasHeaderComment= true;
					}
				}
				IScanner scanner= ToolFactory.createScanner(true, false, false, false);
				scanner.setSource(contents.toCharArray());
				final int shift= range.getOffset();