prefer JDialog over JWindow to avoid focus inversion problem on Compiz (e.g. Ubuntu/Unity 12.10): both JDialog and JFrame happen to work, but JFrame does not support parent nesting;

--- a/src/Tools/jEdit/src/pretty_tooltip.scala	Mon Dec 31 21:01:00 2012 +0100
+++ b/src/Tools/jEdit/src/pretty_tooltip.scala	Mon Dec 31 21:41:22 2012 +0100
@@ -11,7 +11,7 @@
 
 import java.awt.{Color, Point, BorderLayout, Window, Dimension}
 import java.awt.event.{ActionListener, ActionEvent, KeyEvent, WindowEvent, WindowAdapter}
-import javax.swing.{SwingUtilities, JWindow, JPanel, JComponent, KeyStroke}
+import javax.swing.{SwingUtilities, JDialog, JPanel, JComponent, KeyStroke}
 import javax.swing.border.LineBorder
 
 import scala.swing.{FlowPanel, Label}
@@ -28,13 +28,17 @@
   mouse_x: Int, mouse_y: Int,
   results: Command.Results,
   body: XML.Body)
-  extends JWindow(JEdit_Lib.parent_window(parent) getOrElse view)
+  extends JDialog(JEdit_Lib.parent_window(parent) getOrElse view)
 {
   window =>
 
   Swing_Thread.require()
 
 
+  window.setUndecorated(true)
+  window.setFocusableWindowState(true)
+  window.setAutoRequestFocus(true)
+
   window.addWindowFocusListener(new WindowAdapter {
     override def windowLostFocus(e: WindowEvent) {
       if (!Window.getWindows.exists(w =>