What text is in the field, and what kind of field it is? If more text is in the field than is visible you can move up/down in the field to see the additional content... maybe that is what you're seeing?
It happens when text exceeds the width of textfield. If you have no concern with selection of the text, you can keep selectable property false.
textFieldInstance.selectable = false.
yes you are right here, but i have a condition to select the text for creating the comment on that text ,so that i can not make selectable property false.
do u have other option please suggest