Issue Summary

When inserting a "Code Block" macro to an existing pages with the legacy editor no language for syntax highlighting is displayed or can be selected. The select list is blank:

Steps to Reproduce

1. Edit a page using the legacy editor.
2. Tap the insert/"+" button on the editor toolbar and select Code Block
3. Try to select a language under Syntax Highlighting

Expected Results

The available languages for Syntax Highlighting should be listed.

Actual Results

The Syntax Highlighting list shows up empty. On the Developer console a 404 error can be seen for the getlanguages.action call:

Request URL: https://CUSTOMERURL.atlassian.net/wiki/spaces/~557057db37cfa0ddb04984b9e78be007bbf242/pages/edit/null/plugins/newcode/getlanguages.actionRequest 
Method: GET
Status Code: 404 

Workaround

A workaround is to use wiki markup to create a code block. Typing the following and to create a Code Block using the selected language:

{code:language=html/xml}

(If copying and pasting this string you will have to delete and re-type the final curly brace for the Code block to render)

For reference, below is a list of the available languages:

actionscript3
applescript
bash
c#
c
css
coldfusion
delphi
diff
erl
groovy
html/xml
java
javafx
javascript
php
perl
text
powershell
python
ruby
sql
sass
scala
vb