You should change your userChrome.css to the updated:
/* Makes tabs to appear on multiple lines /
/ Tab reordering will not work and can’t be made to work /
/ You can use multi-row_tabs_window_control_patch.css to move window controls to nav-bar*/
/* It’s recommended to move tabs new-tab-button outside tabs toolbar */
/* Change the --multirow-n-rows to change maximum number of rows before the rows will start to scroll /
/ This maximum visible rows won’t work before Fx66 /
/ So this setting does nothing on Fx65 and all tab rows will be shown /
:root{
–multirow-n-rows: 3;
–multirow-tab-min-width: 100px;
–multirow-tab-dynamic-width: 1; / Change to 0 for fixed-width tabs using the above width. */
}
/* Scrollbar can’t be clicked but the rows can be scrolled with mouse wheel /
/ Uncomment the next line if you want to be able to use the scrollbar with mouse clicks */
/* .tabbrowser-arrowscrollbox{ -moz-window-dragging: no-drag } */
/* Uncommenting the above makes you unable to drag the window from empty space in the tab strip but normal draggable spaces will continue to work */
#tabbrowser-tabs{
min-height: unset !important;
padding-inline-start: 0px !important
}
/* Selectors for Firefox 71+ /
/ These are not tabs toolbar specific but horizontal scrollbox isn’t used elsewhere, except in bookmarks toolbar but there it doesn’t have [part] attribute since it’s not in shadow-root */
@-moz-document url(chrome://browser/content/browser.xhtml){
.scrollbutton-up[orient=“horizontal”][part]~spacer,
.scrollbutton-up[orient=“horizontal”][part],
.scrollbutton-down[orient=“horizontal”][part]{ display: none }
scrollbox[part][orient=“horizontal”]{
display: flex;
flex-wrap: wrap;
overflow-y: auto;
max-height: calc(var(–tab-min-height) * var(–multirow-n-rows));
scrollbar-color: currentColor transparent;
scrollbar-width: thin;
}
}
/* Test for Firefox > 66 */
@supports (inset-block:auto){
#tabbrowser-tabs > .tabbrowser-arrowscrollbox > .arrowscrollbox-scrollbox{
display: flex;
flex-wrap: wrap;
overflow-y: auto;
max-height: calc(var(–tab-min-height) * var(–multirow-n-rows));
scrollbar-color: var(–toolbar-bgcolor) var(–lwt-accent-color);
scrollbar-width: thin;
}
#tabbrowser-tabs > .tabbrowser-arrowscrollbox {
overflow: -moz-hidden-unscrollable;
display: block;
}
}
/* Test for Firefox < 66 */
@supports not (inset-block:auto){
#tabbrowser-tabs > .tabbrowser-arrowscrollbox{
min-height: unset !important;
}
#tabbrowser-tabs .scrollbox-innerbox{
display: flex;
flex-wrap: wrap;
}
#tabbrowser-tabs .arrowscrollbox-scrollbox {
overflow: -moz-hidden-unscrollable;
display: block;
}
}
.tabbrowser-tab{ height: var(–tab-min-height); }
#tabbrowser-tabs .tabbrowser-tab[pinned]{
position: static !important;
margin-inline-start: 0px !important;
}
.tabbrowser-tab[fadein]:not([pinned]){
min-width: var(–multirow-tab-min-width) !important;
flex-grow: var(–multirow-tab-dynamic-width);
/*
Uncomment to enable full-width tabs, also makes tab dragging a tiny bit more sensible
Don’t set to none or you’ll see errors in console when closing tabs
*/
/max-width: 100vw !important;/
}
.tabbrowser-tab > stack{ width: 100%; height: 100% }
#tabbrowser-tabs .scrollbutton-up,
#tabbrowser-tabs .scrollbutton-down,
#alltabs-button,
:root:not([customizing]) #TabsToolbar #new-tab-button,
#tabbrowser-tabs spacer,
.tabbrowser-tab::after{ display: none !important }
