Using CodeMirror (3.1.10 (745b2f0) 05:46, 11 August 2015) in combinations with following options:
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with MediaWiki 1.24.4 (see https://wiki.documentfoundation.org/Special:Version )
Is breaking the "show changes" function. It always displays
<pre>
Latest revision Your text
(No difference)
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If it is already resolved, then please add a know issue section to the page ;-)