Bug 99886 [package explorer] Package Explorer focus is not synchronized with the active editor part
During startup Package Explorer tree is closed regardless of the editor currently opened.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
if (object != null) {
						list.add(object);
					}
				} else
					list.add(object);
			}
			return list.toArray();
		}
		/*
		 * @see AbstractTreeViewer#isExpandable(java.lang.Object)
		 */
		public boolean isExpandable(Object parent) {
			if (isFlatLayout())
				return super.isExpandable(parent);
			if (parent instanceof IJavaProject) 
				return super.isExpandable(parent);
			
			ViewerFilter[] filters= fViewer.getFilters();
			Object[] children= ((ITreeContentProvider) fViewer.getContentProvider()).getChildren(parent);
			for (int i = 0; i < children.length; i++) {
				Object object= children[i];
				
				if (isEssential(object))
					return true;
				
				object= filter(object, parent, filters);
				if (object != null)
					return true;
			}
			return false;