How to get the x,y position of a word in a text field ?

[jbv at souslelogo.com]

Hi list,

I have a text field in which users can enter free text and I need
to detect typos in that text and display a list of possible
replacement words under the first word with a typo, this list being
left aligned with the left side of the word.

So far I use "find" followed by "the foundloc", or "select" followed
by "the selectedLoc" but it has to be done inside a "lock screen"
to avoid any display artefact, and it's a bit problematic when the
same  word with the same typo repeats twice in the text...
Is there a faster and less tricky way to do it ?

Thanks
jbv