format_text is not applied to ddwtos choices, preventing MathJax and other filters being applied.

Many users would like to use drag and drop for mathematical questions, in particular we would like students to complete mathematical proofs by dragging and dropping mathematics into the correct place.

To reproduce the problem: Place mathematics with LaTeX inside a choice for a drag and drop question, e.g. ( \int x^2\mathrm{d}x ).  

What I expected: Mathjax would be applied and the user would see the formatted mathematical integral as they would in other places in Moodle, including the question itself.

What actually happens: Mathjax is not applied and the user sees choices containing the raw LaTeX code ( \int x^2\mathrm{d}x ) as one of the drag and drop choices.

 The screen shot attached below shows what happens when you do apply format_text!