Bug 23031 Package explorer does not update when input==package [package explorer]
From a java perspective, create a Java project with two packages (say test.package1 and test.package2). Create a couple of classes in both packages. From the package view, select test.package2 and from the context menu, open a new java window on it. Notice you only see the two classes you created in this package. Now go back to the other window, and move a class from test.package1 to test.package2. Go back to the new window, look at the package view and notice it still only displays 2 classes. Selecting refresh from the context menu does nothing. If you close the package view and open it again, then you see 3 classes.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerContentProvider.java
/*
 * (c) Copyright IBM Corp. 2000, 2002.
 * All Rights Reserved.
 */
package org.eclipse.jdt.internal.ui.packageview;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IResourceDelta;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.swt.widgets.Control;
import org.eclipse.jface.viewers.IBasicPropertyConstants;
import org.eclipse.jface.viewers.ITreeContentProvider;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.jface.viewers.TreeViewer;