Just out!
# New features:
New DOM event forwarded: "dragleave".
protobuf mode: Newly added.
# Bugfixes:
Fix problem where findMarks sometimes failed to find multi-line marks.
Fix crash that showed up when atomic ranges and bidi text were combined.
show-hint addon: Completion widgets no longer close when the line
indented or dedented.
merge addon: Fix bug when merging chunks at the end of the file.
placeholder addon: No longer gets confused by swapDoc.
simplescrollbars addon: Fix invalid state when deleting at end of document.
clike mode: No longer gets confused when a comment starts after an operator.
markdown mode: Now supports CommonMark-style flexible list indentation.
dylan mode: Several improvements and fixes.
You can see all new patches at
https://github.com/codemirror/CodeMirror/compare/5.12.0...5.13.0
Or get the zip from
http://codemirror.net/codemirror-5.13.zip