Index: src/org/openstreetmap/josm/actions/PreferencesAction.java
===================================================================
--- src/org/openstreetmap/josm/actions/PreferencesAction.java	(revision 168)
+++ src/org/openstreetmap/josm/actions/PreferencesAction.java	(revision 169)
@@ -36,7 +36,13 @@
 		JPanel prefPanel = new JPanel(new GridBagLayout());
 		prefPanel.add(prefDlg, GBC.eol().fill(GBC.BOTH));
-		
+
 		JOptionPane pane = new JOptionPane(prefPanel, JOptionPane.PLAIN_MESSAGE, JOptionPane.OK_CANCEL_OPTION);
 		JDialog dlg = pane.createDialog(Main.parent, tr("Preferences"));
+		
+		if (dlg.getWidth() > 600)
+			dlg.setSize(600, dlg.getHeight());
+		if (dlg.getHeight() > 450)
+			dlg.setSize(dlg.getWidth(), 450);
+
 		dlg.setVisible(true);
 		if (pane.getValue() instanceof Integer && (Integer)pane.getValue() == JOptionPane.OK_OPTION)