public void update() {
BrowserInformationControlInput current = fInfoControl.getInput();
if (current != null && current.getPrevious() != null) {
BrowserInput previous = current.getPrevious();
setToolTipText(Messages.format(
PHPHoverMessages.JavadocHover_back_toElement_toolTip,
BasicElementLabels.getJavaElementName(previous
.getInputName())));
setEnabled(true);
} else {
setToolTipText(PHPHoverMessages.JavadocHover_back);
setEnabled(false);