Convert bla to $bla$ automatically when be highlighted and typeset a $.

[Hongyi Zhao]

Hi here,

I want to convert `bla` to `$bla$` automatically when be highlighted
and typeset a `$'.

Currently, my observed result is `bla$$`, which is not consistent with
the LaTeX math environment.

Regards,
Zhao
-- 
Assoc. Prof. Hongsheng Zhao <hongyi.zhao@gmail.com>
Theory and Simulation of Materials
Hebei Vocational University of Technology and Engineering
No. 473, Quannan West Street, Xindu District, Xingtai, Hebei province