Index: tools/config.py
===================================================================
--- tools/config.py	(revision 71385d4f481ab9387c2c2d736bb5f36ca080775f)
+++ tools/config.py	(revision c79d50d2b8365e581e9a038e774700bc00e8e42d)
@@ -338,5 +338,8 @@
 						continue
 					
-					options.append("     %s [%s] --> " % (name, default))
+					if (default == None):
+						options.append("?     %s --> " % name)
+					else:
+						options.append("      %s [%s] --> " % (name, default))
 				elif (vartype == 'y'):
 					defaults[varname] = '*'
@@ -346,10 +349,10 @@
 						default = 'y'
 						defaults[varname] = default
-					options.append(" <%s> %s " % (yes_no(default), name))
+					options.append("  <%s> %s " % (yes_no(default), name))
 				elif (vartype == 'n/y'):
 					if (default == None):
 						default = 'n'
 						defaults[varname] = default
-					options.append(" <%s> %s " % (yes_no(default), name))
+					options.append("  <%s> %s " % (yes_no(default), name))
 				else:
 					raise RuntimeError("Unknown variable type: %s" % vartype)
@@ -378,5 +381,5 @@
 					break
 				else:
-					xtui.error_dialog(screen, 'Error', 'Some options have still undefined values.')
+					xtui.error_dialog(screen, 'Error', 'Some options have still undefined values. These options are marked with the "?" sign.')
 					continue
 			
Index: tools/xtui.py
===================================================================
--- tools/xtui.py	(revision 71385d4f481ab9387c2c2d736bb5f36ca080775f)
+++ tools/xtui.py	(revision c79d50d2b8365e581e9a038e774700bc00e8e42d)
@@ -257,4 +257,4 @@
 	elif (dialog):
 		call_dlg(dlgcmd, '--title', title, '--msgbox', msg, '6', str(width + width_extra))
-	
-	sys.stdout.write("\n%s: %s\n" % (title, msg))
+	else:
+		sys.stdout.write("\n%s: %s\n" % (title, msg))