This #jarchi script shows alternative MessageDialog windows with more options using Java "jface" dialogs

MessageDialogs_JFace.ajs

/*
 * Example message dialogs via jface
 *
 */

 var MessageDialog= Java.type('org.eclipse.jface.dialogs.MessageDialog');

 // Standard Error Message, with "ok" button and error icon
 MessageDialog.openError(shell,"Error","your errortext");

 // Standard Confirm Message, with "ok" and "cancel" button, will return true of false
 var result=MessageDialog.openConfirm(shell,"Confirm","your confirmation request");
 console.log(result);

 // Standard Information Message, with "ok" button and information icon
 MessageDialog.openInformation(shell,"Information","your information");

 // Standard Question Message, with "yes" "no" buttons, returning "true"/"false"
 result=MessageDialog.openQuestion(shell,"Question","your question");
 console.log(result);

 // Standard warning Message, with "ok" button and warning icon
 MessageDialog.openWarning(shell,"Warning","your warningtext");

 // more sophisticated one, you can provide your own buttons, and set the type of standard icon
 // MessageDialog.NONE or .INFORMATION .QUESTION .WARNING .ERROR .CONFIRM
 // returns index within array of button that has been clicked on
 var buttons=["left","middle","right"];
 owndialog = new MessageDialog(shell,"Own messagebox",null,"own messagebox info",MessageDialog.INFORMATION,buttons,0);
 result=owndialog.open();
 console.log(result);