A rough try to add instant preview for ERT. LyX crashes when you hover your mouse over it, but apart from that it seems to work with almost only code copied from InsetMathHull. I guess this can go to some InsetPreview. P.S. I don't know why LyX crashes, but I can't debug right now, so I'll leave it for now.
Vincent
ert-preview.patch
Description: ert-preview.patch
