Bug 30658 Package explorer drag'n drop does not always work
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
IPackageFragment fragment = (IPackageFragment) object;
						return !fragment.isDefaultPackage() && fragment.hasSubpackages();
					}
				} catch (JavaModelException e) {
					JavaPlugin.log(e);
				}
				return false;
			}
			
		};
	}
	/**
	 * Answers whether this part shows the packages flat or hierarchical.
	 * 
	 * @since 2.1
	 */
	boolean isFlatLayout() {
		return fIsCurrentLayoutFlat;
	}
	
	private void setProviders() {
		
		fContentProvider= createContentProvider();
		fContentProvider.setIsFlatLayout(fIsCurrentLayoutFlat);
		fViewer.setContentProvider(fContentProvider);
	
		fLabelProvider= createLabelProvider();
		fLabelProvider.setIsFlatLayout(fIsCurrentLayoutFlat);
		fViewer.setLabelProvider(new DecoratingJavaLabelProvider(fLabelProvider, false, false));