diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4d55958b..17a2795b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,7 @@ CHANGELOG for FlatCAM beta
 - updated the Italian translation
 - updated the translation files
 - changed the line endings for Makefile and setup_ubuntu.sh files
+- protected a dict in VispyVisuals from issuing errors of keys changed while iterating through it
 
 2.05.2020
 
diff --git a/flatcamGUI/VisPyVisuals.py b/flatcamGUI/VisPyVisuals.py
index d6f19d3b..9cf81e54 100644
--- a/flatcamGUI/VisPyVisuals.py
+++ b/flatcamGUI/VisPyVisuals.py
@@ -462,7 +462,7 @@ class ShapeCollectionVisual(CompoundVisual):
         self.update_lock.acquire(True)
 
         # Merge shapes buffers
-        for data in self.data.values():
+        for data in list(self.data.values()):
             if data['visible'] and 'line_pts' in data:
                 try:
                     line_pts[data['layer']] += data['line_pts']