Problem with Top of page in ALV

Hi All,

I have an ALV GRID Interactive report. In my report, the top-of-page is working fine.But, when I double click on report on a table, the font of Header decreasing. Please find the attached image. I have given TOP-OF-PAGE for that report using export parameter I_CALLBACK_TOP_OF_PAGE and FM REUSE_ALV_COMMENTARY_WRITE in the following way. Can I have any solution.

FORM TOP_OF_PAGE.

CALL FUNCTION 'REUSE_ALV_COMMENTARY_WRITE'

EXPORTING

IT_LIST_COMMENTARY = GT_HEADER.

ENDFORM.

Thanks all..