jquery - Modify Invoice Page CSS in Odoo -

i want change css of customer invoice page both sections on right hand side(top section: invoice , bottom one: send message) can have scrollbars , visible @ same time.

see screenshot.

any ideas page edit??

demo page or search google 'odoo demo'. https://demo1.odoo.com/web/#id=12&view_type=form&model=account.invoice&menu_id=304&action=337

give height both frame1 , frame2 , give property overflow-y:scroll