then the best solution is maybe to try to fix it by yourself, then to provide a patch for a better gramps support for this theme!

/usr/share/themes/elementary/gtk-3.0/

==== KDE ====

To set the theme, open gramps, and open '''System settings -> Application Appearance -> GTK+ Appearance''', and select different theme, click on apply. If you see Gramps update completely, you have selected a theme with GTK 3 support. If the theme falls back to something consisting of Raleigh theme components, the theme does not have good GTK 3 support. Even if Gramps updates, not all elements visible will update. Restart Gramps to be sure the theme works as intended. You can install gtk-theme-switch to test themes.