--- a/AbstractFileBrowser.st	Sat Jun 30 18:44:46 2018 +0200
+++ b/AbstractFileBrowser.st	Sat Jun 30 20:34:52 2018 +0200
@@ -8096,20 +8096,22 @@
     "open a change browser on the selected file(s)"
 
     self currentSelectedDirectories notEmptyOrNil ifTrue:[
-        self currentSelectedDirectories do:[:fn |
-            (fn suffix = 'package') ifTrue:[
-                ChangeSetBrowser openOn:(GitHubSmalltalkPackageReader readPackageFrom:fn).
-            ].    
-            (fn suffix = 'class') ifTrue:[
-                ChangeSetBrowser openOn:(GitHubSmalltalkClassReader readPackageFrom:fn).
-            ].    
-        ].
-        ^ self.
+        GitHubSmalltalkPackageReader notNil ifTrue:[
+            self currentSelectedDirectories do:[:fn |
+                (fn suffix = 'package') ifTrue:[
+                    ChangeSetBrowser openOn:(GitHubSmalltalkPackageReader readPackageFrom:fn).
+                ].    
+                (fn suffix = 'class') ifTrue:[
+                    ChangeSetBrowser openOn:(GitHubSmalltalkClassReader readClassFrom:fn).
+                ].    
+            ].
+            ^ self.
+        ].
     ].
     
     self openTool:(UserPreferences current changesBrowserClass)
 
-    "Modified: / 30-06-2018 / 18:35:51 / Claus Gittinger"
+    "Modified: / 30-06-2018 / 20:33:24 / Claus Gittinger"
 !
 
 openDiffView