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
}
	private void postRemove(final Object element) {
		postRunnable(new Runnable() {
			public void run() {
				Control ctrl= fViewer.getControl();
				if (ctrl != null && !ctrl.isDisposed()) {
					fViewer.remove(element);
				}
			}
		});
	}
	
	private void postProjectStateChanged(final Object root) {
		postRunnable(new Runnable() {
			public void run() {
				fPart.projectStateChanged(root);
			}
		});
	}
	private void postRunnable(final Runnable r) {
		Control ctrl= fViewer.getControl();
		final Runnable trackedRunnable= new Runnable() {
			public void run() {
				try {
					r.run();
				} finally {
					removePendingChange();
				}
			}
		};