Bug 286949 [Browser] Bad usage of URL#equals(Object) in WebBrowserEditorInput
HEAD WebBrowserEditorInput#equals(..) calls URL#equals(Object), but the latter resolves the host of the URLs via DNS lookups, which is most of the time not what you want. You should instead compare the strings from URL#toExternalForm(). Furthermore, WebBrowserEditorInput should also override hashCode() (equal objects must have equal hash codes). Note that URL#hashCode() is also broken, so you should use URL#toExternalForm() there as well.
bundles/org.eclipse.ui.browser/src/org/eclipse/ui/internal/browser/WebBrowserEditorInput.java
if (input.isStatusbarVisible() != isStatusbarVisible())
			return false;
		else if (id != null) {
			String bid = input.getBrowserId();
			return id.equals(bid);
		} else
			return false;
	}
	/**
	 * Creates an <code>IElement</code> from the state captured within an
	 * <code>IMemento</code>.
	 * 
	 * @param memento
	 *            a memento containing the state for an element
	 * @return an element, or <code>null</code> if the element could not be
	 *         created
	 */
	public IAdaptable createElement(IMemento memento) {
		int style = 0;
		Integer integer = memento.getInteger(MEMENTO_STYLE);
		if (integer != null) {
			style = integer.intValue();
		}
		URL url = null;
		String str = memento.getString(MEMENTO_URL);
		if (str != null) {
			try {