Ok, ho provato a fare la modifica su OSX e non funziona.
Ho la cartella con i 2 file css: userContent.css vuoto, userChrome.css con la sola riga di default (quella con scritto namespace per intenderci.
Se incollo solo quella parte di codice mi ammucchia tutto: chiedo a chi usa Mac di postarmi il suo file (michro?)
Cancella tutto il testo nel file userChrome.css e incolla questo, (attiva la barra del titolo o si accavalla)
/* TABS: on bottom */
#navigator-toolbox toolbar:not(#nav-bar):not(#toolbar-menubar) {-moz-box-ordinal-group:10}
#TabsToolbar {-moz-box-ordinal-group:1000!important}
#TabsToolbar {
display: block !important;
position: absolute !important;
bottom: 0 !important;
width: 100vw !important;
}
#tabbrowser-tabs {
width: 100vw !important;
}
#main-window:not([chromehidden*="toolbar"]) #navigator-toolbox {padding-bottom: var(--tab-min-height) !important;}
/* TABS: height */
:root {
--tab-toolbar-navbar-overlap: 0px !important;
--tab-min-height: 27px !important; /* adjust to suit your needs */
}
:root #tabbrowser-tabs {
--tab-min-height: 27px !important; /* needs to be the same as above under :root */
--tab-min-width: 80px !important;
}
#TabsToolbar {
height: var(--tab-min-height) !important;
margin-bottom: 1px !important;
box-shadow: ThreeDShadow 0 -1px inset, -moz-dialog 0 1px !important;
}
#tabbrowser-tabs,
#tabbrowser-tabs > .tabbrowser-arrowscrollbox,
.tabbrowser-tabs[positionpinnedtabs] > .tabbrowser-tab[pinned] {
min-height: var(--tab-min-height) !important;
max-height: var(--tab-min-height) !important;
}
/* drag space */
.titlebar-spacer[type="pre-tabs"],
.titlebar-spacer[type="post-tabs"] {
width: 40px;
}
/* Override vertical shifts when moving a tab */
#navigator-toolbox[movingtab] > #titlebar > #TabsToolbar {
padding-bottom: unset !important;
}
#navigator-toolbox[movingtab] #tabbrowser-tabs {
padding-bottom: unset !important;
margin-bottom: unset !important;
}
#navigator-toolbox[movingtab] > #nav-bar {
margin-top: unset !important;
}