Hallo Andreas,
Entfern mal deinen kompl. Inhalt, und füg diesen dafür ein:
CSS Alles anzeigen/*Mehrzeilige Lesezeichen-Symbolleiste*/ @-moz-document url-prefix("chrome://browser/content/browser.xhtml") { #PersonalToolbar { max-height: calc(20px * 3) !important; } #personal-bookmarks, #PlacesToolbar, #PlacesToolbar > hbox { display: block !important; } #PersonalToolbar toolbarbutton { min-height: 20px !important; max-height: 20px !important; } #PlacesToolbarItems { max-height:60px!important; display: flex!important; flex-wrap: wrap!important; overflow-x: visible!important; overflow-y: auto!important; } #PlacesToolbar, #PersonalToolbar > scrollbar { -moz-window-dragging: no-drag !important; } #PlacesToolbar #PlacesChevron { display: none !important; } } @-moz-document url-prefix(chrome://browser/content/browser.xhtml) { #TabsToolbar { min-height: 0px !important; height: 0px !important; visibility: hidden !important; overflow: hidden !important; } } #back-button:not([disabled="true"]):not([open="true"]):not(:active){ fill: blue !important; } #forward-button:not([disabled="true"]):not([open="true"]):not(:active){ fill: blue !important; } /* Zurück-Taste und Vor-Taste: Rahmen um das Grafik-Element. */ #navigator-toolbox #back-button .toolbarbutton-icon, #navigator-toolbox #forward-button .toolbarbutton-icon { border: 1px solid white !important; border-radius: 50% !important; height: 35px !important; width: 35px !important; padding: 6px !important; background-color: white !important; opacity: 1 !important;} #nav-bar .toolbarbutton-1 { filter:none; fill: black!important;} #titlebar-close > .toolbarbutton-icon { width: 16px!important; height: 16px!important; } #titlebar-close{ list-style-image: url("data:image/png;base64,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") !important; }ich hatte das Probem auch. Jetzt ist die Leiste wieder waagerecht aber nicht mehr mehrzeilig. Rechts gibt es jetzt ein Symbol das mir die restlichen Einträge untereinander zeigt. Vielleicht hast Du ja noch eine Idee.
Lutz