1. There is no replace option.
   
2. I suggest use muti-level-criteria for find and replace selection:
   The first level is
   whole document / from mouse point above / from mouse point below /select regions
   
   The second level is
   all / text / math
   
   The third level applies to math only
   all / variable only / subscripts only / superscripts only
   

Wrote

There is no replace option.

Wrote

Replace what, where by what ?
In math regions we have:
click the var/parameter, F8, back space, new.

Wrote

Wrote

There is no replace option.

Replace what, where by what ?
In math regions we have:
click the var/parameter, F8, back space, new.

1. it works for variable only, but it doesn't work for super/sub-script.
   
2. it only work in one region for one time, it not work for multiple regions or the whole document.
   
3. it doesn't work for text regions.
   

Wrote

it works for variable only, but it doesn't work for super/sub-script.

it only work in one region for one time, it not work for multiple regions or the whole document.

it doesn't work for text regions.