emacs - How can I underline marked text to differentiate the text from the pointer? -

when first installed solarized-theme , set recommended values variables here. there great effect of marked text being vertically longer cursor made easier see cursor was. i'm not sure if effect of setting

(setq x-underline-at-descent-line t)  

but after customizing colors of theme bit more, lost effect of saw before anymore (can't seem revert after reinstalling theme either). effect meant marking region (highlighting text) highlight capline down baseline.

sometimes when start emacs. here 1 of lucky times it.

here can see marked region going topline bottomline.

edit: after accidentally getting work again. think desired effect on org headers on 1st/top level. how can effect everywhere?