Avoid null parents when displaying dialogs

According to ChatGPT:
  Sometimes, Java UI components require elevated permissions to manage
  window focus or modal dialogs. When running with lower privileges,
  JOptionPane may be blocked by another process or hidden behind other
  windows, causing an apparent "freeze."

Explicitly creating a parent frame (even if it's not "shown") appears to
be enough to get around these privilige problems.

Closes apposed/jaunch#71

Author: hinerm

src/main/java/org/scijava/launcher/Dialogs.java

@@ -29,10 +29,11 @@
 
 package org.scijava.launcher;
 
-import javax.swing.Icon;
-import javax.swing.JOptionPane;
+import javax.swing.*;
 import java.awt.*;
 import java.lang.reflect.InvocationTargetException;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.CompletableFuture;
@@ -67,9 +68,21 @@ public static Result ask(Component parent,
 				"At least one of yes, no, or never must be non-null");
 		}
 		Object initial = no == null ? options[0] : no;
+
 		CompletableFuture<Integer> future = new CompletableFuture<>();
-		EventQueue.invokeLater(() -> {
-			int result =JOptionPane.showOptionDialog(parent, message, title, optionType, messageType, icon, options, initial);
+		SwingUtilities.invokeLater(() -> {
+			Component parentComp = parent;
+			boolean disposeParent = false;
+			if (parentComp == null) {
+				parentComp = new JFrame();
+				((JFrame)parentComp).setAlwaysOnTop(true);
+				((JFrame)parentComp).setLocationRelativeTo(null); // Ensure it's centered
+				disposeParent = true;
+			}
+			int result = JOptionPane.showOptionDialog(parentComp, message, title, optionType, messageType, icon, options, initial);
+			if (disposeParent) {
+				((JFrame) parentComp).dispose();
+			}
 			future.complete(result);
 		});
 		int choice = 0; // Blocks until dialog completes