Bug 480128

Created attachment 165096 [details]
failing output

SUMMARY
***
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***
Using Pandoc as the preview engine and the filter pandoc-plantuml-filter. If I paste a premade plantuml bloc, the preview is perfect. But if I edit the block, I get an image not found in the preview. However, I checked and Pandoc generated the image. I can find the picture in my personal directory


STEPS TO REPRODUCE
1. use the preview engine pandoc
2. add the custom parameter --filter pandoc-plantuml (with the filter installer and plantuml installed)
3. past the example : 
```plantuml
Alice -> Bob: Authentication Request
Bob --> Alice: Authentication Response

Alice -> Bob: Another authentication Request
Alice <-- Bob: another authentication Response
```
4. modify anything in the example which does not break UML syntax

OBSERVED RESULT

The diagram is not displayed, and instead you get a picture not found replacement. 

EXPECTED RESULT

Get the diagram updated and shown.