en:User talk:GregU/dashes.js is a useful script on English Wikipedia for turning hyhens into dashes. It appears it is no longer works when I use "Wikitext syntax highlighting" beta.
Topic on Extension talk:CodeMirror
@Delusion23 Thanks for letting us know. There are several similar user scripts which break with CodeMirror. It seems like the script author isn't active on wiki anymore, unfortunately. We'll try to take a look at it.
CodeMirror breaks any script wich need manipulating plain Wiki text. To need fix every script except of CodeMirror is an absolute no-go. Why need CodeMirror a new Textbox? Other older (sometimes better) Syntax-highlighter have not this problem (my favorite is de:User:Schnark/js/syntaxhighlight).
PS: There is a difference in the textbox access .
$( '#wpTextbox1' ).val() is different to $( '#wpTextbox1' ).value
Which is normally fully the same, but seems a use of hook or something.