Branding is lost when hover windows opens up

Currently we are upgrading Tools Release Portal – 9.1, v8.53 HR – 9.0 , v8.53 We have Portal Application running with HCM acting as content provider application. Our HCM application is having PSSTYLEDEF as the stylesheet. Now when we are accessing the HR Component from the portal application (Here HR Component is the content provider), the Portal branding is applied on the content provider page which is working as expected. But upon opening Modal window from the Portal page (Say for example – Prompt window, spell check window etc), the buttons/stylesheet are being applied as that of the HR instead