Syntax highlighting inactive in new cells

[ysalmon]

I am using the iocaml-kernel with Jupyter and syntax highlighting does not completely work.
If I open a notebook that contains OCaml code, it gets highlighted.

However, if I create a new code cell and type code in it, it does not. Validating the cell does not trigger syntax highlighting either.

Saving and reloading the notebook gives a correctly highlighted code in the new cell. If I re-edit this cell, syntax highlighting works !

This allows to make notebooks that look nice in the end, but syntax highlighting would be really useful while typing !

Jupyter notebooks using the Python3 kernel are correctly highlighted from the beginning.