Thank you very much Nadya
I did inserted your codes, unfortunately it highlighted the entire contents of the editbox.

txtSearch=upper(ALLtrim(thisform.contSearch.txtSearch.value))
loca for txtSearch $ UPPER(edtsummary)
lnPos=at(txtSearch,upper(thisform.edtsummary.value))
if m.lnPos>0
thisform.edtsummary.SelStart=m.lnPos
thisform.edtsummary.SelLength=len(txtSearch)
endif
thisform.refresh