diff --git a/FlatCAMApp.py b/FlatCAMApp.py
index 9feb51d7..29b8511e 100644
--- a/FlatCAMApp.py
+++ b/FlatCAMApp.py
@@ -9587,6 +9587,11 @@ class App(QtCore.QObject):
                              _("Select an Gerber or Excellon file to view it's source file."))
             return 'fail'
 
+        if obj is None:
+            self.inform.emit('[WARNING_NOTCL] %s' %
+                             _("Select an Gerber or Excellon file to view it's source file."))
+            return 'fail'
+
         flt = "All Files (*.*)"
         if obj.kind == 'gerber':
             flt = "Gerber Files (*.GBR);;All Files (*.*)"
diff --git a/README.md b/README.md
index b3484c16..d1a05ea1 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,7 @@ CAD program, and create G-Code for Isolation routing.
 21.10.2019
 
 - the context menu for the Tabs in notebook and PlotTabArea is launched now on right mouse click on tabs themselves
+- fixed an error when trying to view the source file and there is no object selected
 
 18.10.2019