[rams]

Hm, inace ne koristim FF, ali evo ako sam ja sve dobro shvatio ovako bi trebalo napraviti:

Idi u mapu C:\Program Files\Mozilla Firefox\chrome\ i ondje napravi userChrome.txt, zatim u njega kopiraj sljedece:

menupopup, popup {
border: 2px solid !important;
-moz-border-top-colors: ThreeDLightShadow ThreeDHighlight;
-moz-border-right-colors: ThreeDDarkShadow ThreeDShadow;
-moz-border-bottom-colors: ThreeDDarkShadow ThreeDShadow;
-moz-border-left-colors: ThreeDLightShadow ThreeDHighlight;
padding: 1px !important;
}
menubar > menu[disabled="true"] {
border: 1px solid transparent !important;
}
menubar > menu[_moz-menuactive="true"] {
border-top: 1px solid ThreeDHighlight !important;
border-right: 1px solid ThreeDShadow !important;
border-bottom: 1px solid ThreeDShadow !important;
border-left: 1px solid ThreeDHighlight !important;
background-color: transparent !important;
color: MenuText !important;
}
menubar > menu[_moz-menuactive="true"][open="true"] {
border-top: 1px solid ThreeDShadow !important;
border-right: 1px solid ThreeDHighlight !important;
border-bottom: 1px solid ThreeDHighlight !important;
border-left: 1px solid ThreeDShadow !important;
}

zatom samo promjeni ekstenziju u userChrome.css

Eto, javi ako radi, ako ne onda neznam

ps. moze rep up