Wikimedia Bugzilla is closed!

Intention:
I use the GraphViz extension v1.3.0 on top of MediaWiki v1.19.17 to draw diagrams from DOT code. The diagram is created in the correct way. But when updating the DOT code and saving the MediaWiki page again the diagram is not updated (the old diagram is shown.)

Steps to Reproduce:
1. Versions: MediaWiki 1.19.17, GraphViz extension 1.3.0
2. Create a page with a simple GraphViz example on it:
== simple graphViz test ==

=== Example 1 from http://www.mediawiki.org/wiki/Extension:GraphViz ===
<graphviz border='frame' format='png'>
digraph example1 {Hello->"World!"}
</graphviz>

3. Save the page.
4. The page is shown with the diagram in the correct way. 
5. Edit the DOT code on the page, e.g. add another node and edge:
== simple graphViz test ==

=== Example 1 from http://www.mediawiki.org/wiki/Extension:GraphViz ===
<graphviz border='frame' format='png'>
digraph example1 {Hello->"World!";
Hello->Goodbye;}
</graphviz>

6. Save the changes
7. The old diagram is shown without the additional node "Goodbye" and the edge from "Hello" to "Goodbye"

Actual Results:  
The old diagram is shown.

Expected Results:  
The updated diagram should be shown.

Reproducible: Always