1 files changed, 5 insertions, 0 deletions
diff --git a/TurtleArt/talogo.py b/TurtleArt/talogo.py
index 944b9bf..3d5d290 100644
--- a/TurtleArt/talogo.py
+++ b/TurtleArt/talogo.py
@@ -22,6 +22,7 @@
 #THE SOFTWARE.
 
 import gtk
+import gobject
 from time import time
 
 from operator import isNumberType
@@ -425,16 +426,20 @@ class LogoCode:
 
     def doevalstep(self):
         """ evaluate one step """
+        self.tw.event.wait()
         starttime = _millisecond()
         try:
             while (_millisecond() - starttime) < 120:
                 try:
                     if self.step is not None:
+                        self.tw.lock.acquire()
                         self.step.next()
+                        self.tw.lock.release()
                     else:
                         return False
                 except StopIteration:
                     # self.tw.turtles.show_all()
+                    self.tw.lock.release()  # Just in case.
                     if self.hidden_turtle is not None:
                         self.hidden_turtle.show()
                         self.hidden_turtle = None