A dialog can be either modal or modeless.
A modal dialog blocks user input to all other windows in the same application when it is visible. You have to close a modal dialog before other windows in the same application can get focus.
A modeless one does not block user input.
A dialog can belong to another dialog or a frame. Or, it can stand alone like a JFrame.
class Help extends JDialog {
Help(Frame frame, String title) {
super(frame, title);
setModalExclusionType(Dialog.ModalExclusionType.APPLICATION_EXCLUDE);
try {
JEditorPane ep = new JEditorPane("file:///" + new File("").getAbsolutePath() + "/uchelp.html");
ep.setEnabled(false);
getContentPane().add(ep);
} catch (IOException ioe) {
JOptionPane.showMessageDialog(frame, "Unable to install editor pane");
return;
}
setSize(200, 200);
setLocationRelativeTo(frame);
setVisible(true);
}
}