protected void handleButtonPressed(Button widget) {
try {
IType throwable = JdtUtils.getJavaType(WebflowUtils.getActiveWebflowConfig()
.getProject().getProject(), "java.lang.Throwable");
IJavaSearchScope searchScope = SearchEngine.createJavaSearchScope(throwable
.newTypeHierarchy(new NullProgressMonitor()).getAllSubtypes(throwable));
FilteredTypesSelectionDialog dialog = new FilteredTypesSelectionDialog(getShell(), false,
new ProgressMonitorDialog(getShell()), searchScope, IJavaSearchConstants.CLASS);
dialog.setBlockOnOpen(true);
dialog.setTitle("Type Selection");