popup menu grabs all input events when shown via show()

michael.bundschuh@Eng 1997-01-07
Once a popup menu is shown via show(), it captures all
keyboard and mouse input until a mouse SELECT or MENU is generated.

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import java.awt.*;
import java.applet.*;

/**
 * Tests the PopupMenu class
 *
 * You can run this applet with the command:
 *
 * appletviewer PopupMenuTest.java
 *
 * The following line is needed for the appletviewer to find.
 *
 * <applet code="PopupMenuTest.class" width=200 height=200> </applet>
 */
public class PopupMenuTest extends Applet {

        PopupMenu popup;

        public void init() {

                popup = new PopupMenu("Edit Menu");
                popup.add("Cut");
                popup.add("Copy");
                popup.add("Paste");

                add(popup);
                resize(200, 200);

                // Note the frame must be showing before the popup can be shown,
                // as described in the documentation.
                show();

                // Bug: this grabs all input until a mouse SELECT or MENU
                // button is pressed. This is very anti-social; I would expect
                // the input behavior to be unimpeded. In the case this is
                // not considered a bug, it should be documented better on how
                // to correctly use the show() statement.
                popup.show( this, 0, 0);
        }


        public boolean
        handleEvent( Event evt ) {
                if ( evt.id == Event.MOUSE_DOWN ) {
                        popup.show( (Component)evt.target, evt.x, evt.y );
                        return true; // event handled
                }
                return super.handleEvent(evt);
        }


        public boolean
        action( Event evt, Object arg ) {

                if ( "Cut".equals(arg) ) {
                        System.out.println("Cut");
                        return true;
                } else if ( "Copy".equals(arg) ) {
                        System.out.println("Copy");
                        return true;
                } else if ( "Paste".equals(arg) ) {
                        System.out.println("Paste");
                        return true;
                }

                return false ; // event needs to be handled
        }

} // class PopupMenuTest

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