Cursor behaves weirdly in the composer - it disappears as I move it up/down

[sam (Sam Saffron)]

@meglio

Is this because jsfiddle uses their own rendering mechanism of the cursor while Discourse uses the default textarea and thus is affected by the default cursor Firefox behaviour?

JSFiddle is not using a TEXTAREA it is using a contenteditable HTML element, TEXTAREA does not support all that highlighting.

Recommend you post on that Firefox bug I linked, looks exactly like what you are seeing.