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Tab bar (all tabs) missing in Firefox 90

  • 8 uphendule
  • 1 inale nkinga
  • 3 views
  • Igcine ukuphendulwa ngu RemySecor

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I just got my upgrade from Firefox86 to Firefox90 working, but the tab bar is completely missing.

I still use "old-style" FIrefox. From top to bottom: File/Edit/View menu Search bar Bookmarks Toolbar Tab bar

(yes, I AM old. I've been using Firefox since Version 1 and this particular style works for me, developers be damned.)

The tab bar is completely missing. Firefox knows how many tabs I have open (it warns me when I try to exit) but doesn't show any. The area that the Tab Bar used to occupy is simply empty.

Any ideas on how to fix? (Yes, I have done the Google.)

I just got my upgrade from Firefox86 to Firefox90 working, but the tab bar is completely missing. I still use "old-style" FIrefox. From top to bottom: File/Edit/View menu Search bar Bookmarks Toolbar Tab bar (yes, I AM old. I've been using Firefox since Version 1 and this particular style works for me, developers be damned.) The tab bar is completely missing. Firefox knows how many tabs I have open (it warns me when I try to exit) but doesn't show any. The area that the Tab Bar used to occupy is simply empty. Any ideas on how to fix? (Yes, I have done the Google.)

Isisombululo esikhethiwe

You can try this change. If it doesn't work and I haven't tested the code as it mainly is code for Windows and I'm not on that platform then best is to go to Firefox CSS subreddit.

Old code:

#main-window:not([chromehidden*="toolbar"]) #navigator-toolbox {
  padding-bottom: calc(1px + var(--tab-min-height_tnot)) !important;
}

New code:

#main-window:not([chromehidden*="toolbar"]) #navigator-toolbox {
  padding-bottom: calc(1px + var(--tab-min-height_tnot)) !important;
  position: relative !important;
}

Funda le mpendulo ngokuhambisana nalesi sihloko 👍 1

All Replies (8)

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See this forum response for updated CSS code for Firefox 89+:

DISCLAIMER: modifications made through a userChrome.css file can stop working as Firefox evolves in new releases, and can "break" the interface in serious ways.

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cor-el: That link has adjustments for Firefox 69 and above. I am already using Firefox 86 with userChrome.css and in that version of the browser the tab bar shows below the bookmarks toolbar, so that doesn't seem to apply to my situation.

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If I go into settings for Toolbars, I can see the tabs at the bottome of the browser screen, overlapping the Settings options.

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This is what my current userChrome.css file looks like. Is there some simple change I can make to it? PART 1

/* Firefox Quantum userChrome.css tweaks ************************************************/
/* Github: https://github.com/aris-t2/customcssforfx ************************************/
/* THIS EXTRACT combines two files from the above repository:
   https://github.com/Aris-t2/CustomCSSforFx/blob/master/classic/css/tabs/tabs_below_navigation_toolbar.css
   version 2.3.9 as of Feb. 2, 2019
   https://github.com/Aris-t2/CustomCSSforFx/blob/master/classic/css/tabs/tabs_below_navigation_toolbar_fx65.css
   version 2.4.4 as of Feb. 22, 2019
*/
/****************************************************************************************/

:root {
  --colored_menubar_background_image: linear-gradient(#f9f9fa,#f9f9fa);
  --general_toolbar_color_toolbars: linear-gradient(#f9f9fa,#f9f9fa);
  --general_toolbar_color_navbar: linear-gradient(#f9f9fa,#f9f9fa);
  --tabs_toolbar_color_tabs_not_on_top: linear-gradient(#f9f9fa,#f9f9fa);
  --tabs_toolbar_border-tnot_normal_mode_size: 1px;
  --tabs_toolbar_border-tnot_normal_mode: var(--tabs-border-color);
  --classic_squared_tabs_tab_text_color: black;
  --classic_squared_tabs_new_tab_icon_color: black;
  --classic_squared_tabs_tab_text_shadow: transparent;
  --tab-min-height_tnot: 32px;
}

:root[uidensity=compact]  {
  --tab-min-height_tnot: 28px;
}

:root[uidensity=touch] {
  --tab-min-height_tnot: 40px;
}

/* tabs toolbar adjustment */
#main-window[tabsintitlebar] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[tabsintitlebar][sizemode="maximized"] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[uidensity=compact][tabsintitlebar] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[uidensity=compact][tabsintitlebar][sizemode="maximized"] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#TabsToolbar {
  -moz-padding-start: 2px !important;
}

#main-window[tabsintitlebar] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar:-moz-lwtheme,
#main-window[tabsintitlebar][sizemode="maximized"] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar:-moz-lwtheme,
#main-window[uidensity=compact][tabsintitlebar] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar:-moz-lwtheme,
#main-window[uidensity=compact][tabsintitlebar][sizemode="maximized"] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar:-moz-lwtheme,
#TabsToolbar:-moz-lwtheme,
#main-window[tabsintitlebar][sizemode="maximized"] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[uidensity=compact][tabsintitlebar][sizemode="maximized"] #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[sizemode="maximized"] #TabsToolbar,
#main-window[tabsintitlebar]:not([style*='--lwt-header-image']):-moz-lwtheme #navigator-toolbox #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[tabsintitlebar][sizemode="maximized"]:not([style*='--lwt-header-image']):-moz-lwtheme #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[uidensity=compact][tabsintitlebar]:not([style*='--lwt-header-image']):-moz-lwtheme #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[uidensity=compact][tabsintitlebar][sizemode="maximized"]:not([style*='--lwt-header-image']):-moz-lwtheme #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[tabsintitlebar]:not([style*='--lwt-header-image']):-moz-lwtheme #TabsToolbar {
  -moz-padding-start: 0px !important;
}

#main-window[tabsintitlebar][sizemode="normal"]:not([sizemode="fullscreen"]) #TabsToolbar {
  margin-top: 0px !important;
}

#main-window[tabsintitlebar][sizemode="normal"][chromehidden~="menubar"] #TabsToolbar,
#main-window[tabsintitlebar][sizemode="normal"] #toolbar-menubar[autohide="true"][inactive] + #TabsToolbar,
#main-window[tabsintitlebar][sizemode="maximized"][chromehidden~="menubar"] #TabsToolbar,
#main-window[tabsintitlebar][sizemode="maximized"] #toolbar-menubar[autohide="true"][inactive] + #TabsToolbar {
  padding-top: 0px !important;
}

#main-window[tabsintitlebar] #toolbar-menubar[autohide="true"]:not([inactive="true"]) ~ #TabsToolbar,
#main-window[tabsintitlebar] #toolbar-menubar[autohide="false"] ~ #TabsToolbar{
  margin-top: 0px !important;
}

/* tab title in titlebar support */
#main-window[tabsintitlebar][sizemode="normal"] #navigator-toolbox #TabsToolbar,
#main-window[uidensity=compact][tabsintitlebar][sizemode="normal"] #navigator-toolbox #TabsToolbar,
#main-window[tabsintitlebar][sizemode="maximized"] #navigator-toolbox #TabsToolbar,
#main-window[uidensity=compact][tabsintitlebar][sizemode="maximized"] #navigator-toolbox #TabsToolbar,
#main-window[tabsintitlebar][sizemode="normal"] #navigator-toolbox #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[uidensity=compact][tabsintitlebar][sizemode="normal"] #navigator-toolbox #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[tabsintitlebar][sizemode="maximized"] #navigator-toolbox #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[uidensity=compact][tabsintitlebar][sizemode="maximized"] #navigator-toolbox #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar{
  margin-top: 0px !important;
}

/* titlebar button support */
#main-window[tabsintitlebar] #toolbar-menubar[autohide="true"][inactive="true"] ~ #nav-bar{
  margin-top: 2px !important;
}

/* fix for application/hamburger button in titlebar */
#main-window[tabsintitlebar][sizemode="fullscreen"] #toolbar-menubar[autohide="true"][inactive="true"] ~ #nav-bar #PanelUI-button {
  visibility: collapse !important;
}

#main-window[inDOMFullscreen="true"] #TabsToolbar {
  opacity: 0 !important;
}

/* tab height */
#tabbrowser-tabs,
#tabbrowser-tabs > .tabbrowser-arrowscrollbox,
.tabbrowser-tabs[positionpinnedtabs] > .tabbrowser-tab[pinned] {
  min-height: var(--tab-min-height_tnot) !important;
}

/* toolbar order (start) ************************************/
#print-preview-toolbar,
#printedit-toolbar,
#titlebar {
  -moz-box-ordinal-group: 0 !important;
}
#navigator-toolbox #toolbar-menubar {
  -moz-box-ordinal-group: 1 !important;
}
/* navigation toolbar */
#navigator-toolbox #nav-bar {
  -moz-box-ordinal-group: 2 !important;
}
/* bookmarks toolbar */
#navigator-toolbox #PersonalToolbar {
  -moz-box-ordinal-group: 3 !important;
}
/* 3rd party toolbars */
#navigator-toolbox toolbar {
  -moz-box-ordinal-group: 10 !important;
}
/* tabs toolbar */
#navigator-toolbox #TabsToolbar {
  -moz-box-ordinal-group: 100 !important;
}
/* toolbar order (end) **************************************/

/* toolbar colors */
#main-window:not([tabsintitlebar]) #toolbar-menubar:not(:-moz-lwtheme) {
  background-image: var(--colored_menubar_background_image) !important;
  border: 0px !important;
  margin-bottom: -1px !important;
}

#nav-bar:not(:-moz-lwtheme) {
  -moz-appearance: none !important;
  background: var(--general_toolbar_color_navbar, inherit) !important;
}

toolbar:not(#TabsToolbar):not(#toolbar-menubar):not(#nav-bar):not(:-moz-lwtheme) {
  -moz-appearance: none !important;
  background: var(--general_toolbar_color_toolbars, inherit) !important;
}
#TabsToolbar:not(:-moz-lwtheme){
  -moz-appearance: none !important;
  background-image: var(--tabs_toolbar_color_tabs_not_on_top) !important;
}

/* remove color overlay for lw-themes */
#main-window[style*='--lwt-header-image'] :-moz-any(#nav-bar,#PersonalToolbar,#TabsToolbar):-moz-lwtheme{
  background: unset !important;
}

/* adjust compact themes background color */
#main-window:not([style*='--lwt-header-image']) #TabsToolbar:-moz-lwtheme {
  -moz-appearance: none !important;
  background-image: linear-gradient(var(--toolbar-bgcolor),var(--toolbar-bgcolor)) !important;
}

#main-window:not(:-moz-lwtheme) #TabsToolbar :-moz-any(.tabs-newtab-button,.scrollbutton-up,.scrollbutton-down),
#main-window:not(:-moz-lwtheme) #TabsToolbar > toolbarbutton,
#main-window:not([style*='--lwt-header-image']):-moz-lwtheme:-moz-lwtheme-darktext #TabsToolbar :-moz-any(.tabs-newtab-button,.scrollbutton-up,.scrollbutton-down),
#main-window:not([style*='--lwt-header-image']):-moz-lwtheme:-moz-lwtheme-darktext #TabsToolbar > toolbarbutton {
  fill: var(--classic_squared_tabs_new_tab_icon_color) !important;
  color: var(--classic_squared_tabs_new_tab_icon_color) !important;
}

/* toolbar borders */
#main-window #navigator-toolbox::after {
  opacity: 0 !important;
}

#TabsToolbar{
  margin-bottom: 0px !important;
  border-bottom: 1px solid #5f7181 !important;
}

#main-window[sizemode="normal"] #navigator-toolbox :-moz-any(#nav-bar,#PersonalToolbar,#TabsToolbar) {
  border-left: var(--tabs_toolbar_border-tnot_normal_mode_size) solid var(--tabs_toolbar_border-tnot_normal_mode) !important;
  border-right: var(--tabs_toolbar_border-tnot_normal_mode_size) solid var(--tabs_toolbar_border-tnot_normal_mode) !important;
  background-clip: padding-box !important;
}

#main-window[sizemode="maximized"] #navigator-toolbox :-moz-any(#nav-bar,#PersonalToolbar,#TabsToolbar) {
  border-left: 0px !important;
  border-right: 0px !important;
}

#main-window[style*='--lwt-header-image'][sizemode="normal"] #navigator-toolbox :-moz-any(#nav-bar,#PersonalToolbar,#TabsToolbar):-moz-lwtheme,
#main-window[style*='--lwt-header-image'][sizemode="maximized"] #navigator-toolbox :-moz-any(#nav-bar,#PersonalToolbar,#TabsToolbar):-moz-lwtheme {
  border-top: 0px !important;
  border-left: 0px !important;
  border-right: 0px !important;
}

Okulungisiwe ngu cor-el

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Part 2:

#main-window:not([style*='--lwt-header-image']):-moz-lwtheme-brighttext #TabsToolbar:-moz-lwtheme {
  border-bottom: 1px solid #323234 !important;
}

#main-window:not([style*='--lwt-header-image']):-moz-lwtheme:-moz-lwtheme-brighttext #TabsToolbar:-moz-lwtheme {
  border-bottom: 1px solid #323234 !important;
}

#main-window:not([sizemode="fullscreen"])[tabsintitlebar] #TabsToolbar{
  -moz-margin-end: 0px !important;
}

#main-window[tabsintitlebar] #TabsToolbar .titlebar-placeholder{
  visibility: collapse !important;
}

#main-window[tabsintitlebar][sizemode="normal"] #toolbar-menubar[autohide="true"][inactive="true"] {
  margin-top: 21px !important;
}
#main-window[tabsintitlebar][sizemode="maximized"] #toolbar-menubar[autohide="true"][inactive="true"] {
  margin-top: 20px !important;
}

#tabbrowser-tabs .tab-drop-indicator {
  margin-bottom: 0px !important;
}

#PersonalToolbar:-moz-lwtheme,
#nav-bar:-moz-lwtheme {
  background-image: none !important;
  box-shadow: none !important;
  border-top: none !important;
  border-bottom: none !important;
}

/* remove tab fog */
#TabsToolbar:not(:-moz-lwtheme),
#TabsToolbar:not(:-moz-lwtheme)::before,
#TabsToolbar:not(:-moz-lwtheme)::after {
  box-shadow: unset !important;
}

/* remove 'dragging tab' margin/padding nonsense */
#TabsToolbar[movingtab] {
  padding-bottom: unset !important;
}

#TabsToolbar[movingtab] > .tabbrowser-tabs {
  padding-bottom: unset !important;
  margin-bottom: unset !important;
}

#TabsToolbar[movingtab] + #nav-bar {
  margin-top: unset !important;
}

/* scroll buttons */
#TabsToolbar:not(:-moz-lwtheme) #alltabs-button,
#TabsToolbar:not(:-moz-lwtheme) .tabbrowser-arrowscrollbox > .scrollbutton-up,
#TabsToolbar:not(:-moz-lwtheme) .tabbrowser-arrowscrollbox > .scrollbutton-down {
  fill: black !important;
}

/* Fx58+ titlebar placeholders */
#TabsToolbar *[type="pre-tabs"],
#TabsToolbar *[type="post-tabs"] {
  display: none !important;
}

@media (-moz-os-version: windows-win10) {
	#main-window[tabsintitlebar][sizemode="normal"] #toolbar-menubar[autohide="true"][inactive="true"] {
	  margin-top: 30px !important;
	}
	#main-window[tabsintitlebar][sizemode="maximized"] #toolbar-menubar[autohide="true"][inactive="true"] {
	  margin-top: 30px !important;
	}
}

@media (-moz-windows-classic) {

	/* tweaks for Windows Classic theme */
	#nav-bar:not(:-moz-lwtheme),
	#PersonalToolbar:not(:-moz-lwtheme),
	#main-window:not([tabsintitlebar])  #TabsToolbar:not(:-moz-lwtheme) {
	  border-left: unset !important;
	  border-right: unset !important;
	  background: unset !important;
	}

	#main-window[sizemode="normal"] #navigator-toolbox :-moz-any(#nav-bar,#PersonalToolbar,#TabsToolbar) {
	  border-left: 0px !important;
	  border-right: 0px !important;
	}

	#main-window:not([tabsintitlebar]) #toolbar-menubar:not(:-moz-lwtheme) {
	  background: unset !important;
	  box-shadow: unset !important;
	  border-bottom: unset !important;
	}

	#main-window:not([tabsintitlebar]):not(:-moz-lwtheme) #navigator-toolbox,
	#main-window:not([tabsintitlebar]):not(:-moz-lwtheme) #nav-bar,
	#main-window:not([tabsintitlebar]):not(:-moz-lwtheme) #navigator-toolbox::before,
	#main-window:not([tabsintitlebar]):not(:-moz-lwtheme) #nav-bar::before,
	#main-window:not([tabsintitlebar]):not(:-moz-lwtheme) #navigator-toolbox::after,
	#main-window:not([tabsintitlebar]):not(:-moz-lwtheme) #nav-bar::after {
	  background: unset !important;
	  box-shadow: unset !important;
	  border: unset !important;
	  border-image: unset !important;
	}

	#main-window:not([tabsintitlebar]) toolbar:not(#TabsToolbar):not(#toolbar-menubar):not(#nav-bar):not(:-moz-lwtheme) {
	  background: unset !important;
	}

}

/* tab text colors */
#TabsToolbar:not(:-moz-lwtheme) .tabbrowser-tab {
  color: var(--classic_squared_tabs_tab_text_color) !important;
  text-shadow: 1px 1px 1px var(--classic_squared_tabs_tab_text_shadow) !important;
}

/* fix Windows 7s default tab background (remove dark purple bg color)*/
@media (-moz-os-version: windows-win7) {
  @media (-moz-windows-default-theme) {
    .tabbrowser-tab:not([selected]):not(:hover):not(:-moz-lwtheme) {
      background-color: #e3e4e6 !important;
    }
	.tabbrowser-tab:not([selected]):hover:not(:-moz-lwtheme) {
      background-color: #cccdcf !important;
    }

  }
}

/* Simple Close Tab button */
#TabsToolbar:not(:-moz-lwtheme) #_fe8cab45-aaee-45f8-8765-781e0ebea300_-browser-action {
  --webextension-toolbar-image-light: url("moz-extension://7904448c-2319-4f6f-aac9-a1f701258098/icons/Close-dark.svg") !important;
}

/* close tab button */
#TabsToolbar:not(:-moz-lwtheme) #closetab_fmarin_com-browser-action {
  --webextension-toolbar-image-light: url("moz-extension://31006e48-8e00-476f-8ea9-697e40934b02/icons/icon.svg") !important;
  --webextension-toolbar-image-2x-light: url("moz-extension://31006e48-8e00-476f-8ea9-697e40934b02/icons/icon.svg") !important;
}

/* close window button */
#TabsToolbar:not(:-moz-lwtheme) #close-window-button_nanpuyue_com-browser-action {
  --webextension-toolbar-image-light: url("moz-extension://c914bd13-793f-4a2d-ab66-c655a3d75c52/icons/icon.svg") !important;
  --webextension-toolbar-image-2x-light: url("moz-extension://c914bd13-793f-4a2d-ab66-c655a3d75c52/icons/icon.svg") !important;
}

/*
   Start Firefox 65 fix:
   https://github.com/Aris-t2/CustomCSSforFx/blob/master/classic/css/tabs/tabs_below_navigation_toolbar_fx65.css
   Lines 1-10 omitted
*/

#main-window:not([chromehidden*="toolbar"]) #navigator-toolbox {
  padding-bottom: calc(1px + var(--tab-min-height_tnot)) !important;
}

#TabsToolbar {
  position: absolute !important;
  bottom: 0 !important;
  width: 100vw !important;
}

#tabbrowser-tabs {
  width: 100vw !important;
}

/* make sure button icon colors set correctly */
#main-window:not(:-moz-lwtheme) #TabsToolbar-customization-target toolbarbutton .toolbarbutton-icon,
#main-window:not([style*='--lwt-header-image']):-moz-lwtheme:-moz-lwtheme-darktext #TabsToolbar-customization-target toolbarbutton .toolbarbutton-icon {
  fill: var(--classic_squared_tabs_new_tab_icon_color) !important;
  color: var(--classic_squared_tabs_new_tab_icon_color) !important;
}

#main-window[tabsintitlebar]:not([inDOMFullscreen="true"]) #toolbar-menubar .titlebar-buttonbox-container {
  display: none !important;
}

/* move caption buttons to windows top right position */
#main-window[tabsintitlebar]:not([inDOMFullscreen="true"]) #toolbar-menubar ~ #TabsToolbar .titlebar-buttonbox-container {
  position: fixed !important;
  right: 0 !important;
  visibility: visible !important;
  display: block !important;
}

/* caption button position in maximized mode after moving to the top */
#main-window[tabsintitlebar]:not([inDOMFullscreen="true"]) #toolbar-menubar ~ #TabsToolbar .titlebar-buttonbox-container,
#main-window[tabsintitlebar][sizemode="maximized"]:not([inDOMFullscreen="true"]) #TabsToolbar .titlebar-buttonbox-container {
  top: -14px !important;
}

Okulungisiwe ngu cor-el

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Part 3:

/* Windows */
@media (-moz-os-version:windows-win10), (-moz-os-version:windows-win8), (-moz-os-version:windows-win7) {
	#main-window[tabsintitlebar]:not([inDOMFullscreen="true"]) #toolbar-menubar ~ #TabsToolbar .titlebar-buttonbox-container	{
	  top: 1px !important;
	}
	#main-window[tabsintitlebar][sizemode="maximized"]:not([inDOMFullscreen="true"]) #toolbar-menubar ~ #TabsToolbar .titlebar-buttonbox-container {
	  top: 8px !important;
	}
}

/* Windows 7/8 extra tweaks */
@media (-moz-os-version: windows-win7) {
  @media all and (-moz-windows-compositor) {
	#main-window[tabsintitlebar]:not([inDOMFullscreen="true"]) #toolbar-menubar ~ #TabsToolbar .titlebar-buttonbox-container {
	  display: none !important;
	}
	#main-window[tabsintitlebar]:not([inDOMFullscreen="true"]):-moz-lwtheme #toolbar-menubar ~ #TabsToolbar .titlebar-buttonbox-container {
	  display: block !important;
	  margin-top: -13px !important;
	}
  }
  @media not all and (-moz-windows-compositor) {
	#main-window[tabsintitlebar]:not([inDOMFullscreen="true"]) #toolbar-menubar ~ #TabsToolbar .titlebar-buttonbox-container {
	  top: -2px !important;
	}
	#main-window[tabsintitlebar][sizemode="maximized"]:not([inDOMFullscreen="true"]) #toolbar-menubar ~ #TabsToolbar .titlebar-buttonbox-container {
	  top: 0px !important;
	}
  }
}

@media (-moz-os-version:windows-win8) {
	#main-window[tabsintitlebar]:not([inDOMFullscreen="true"]) #toolbar-menubar ~ #TabsToolbar .titlebar-buttonbox-container	{
	  top: -13px !important;
	}
	#main-window[tabsintitlebar][sizemode="maximized"]:not([inDOMFullscreen="true"]) #toolbar-menubar ~ #TabsToolbar .titlebar-buttonbox-container {
	  top: -5px !important;
	}
}


/* Windows 10 extra tweaks */
@media (-moz-os-version: windows-win10) {
  #main-window:not([tabsintitlebar]) menubar > menu:not(:-moz-lwtheme):hover:not([disabled="true"]),
  #main-window:not([tabsintitlebar]) menubar > menu:not(:-moz-lwtheme)[_moz-menuactive="true"]:not([disabled="true"]) {
	background-color: Highlight !important;
	color: HighlightText !important;
  }
}

/* tweaks for fullscreen mode */
#main-window[tabsintitlebar][sizemode="fullscreen"] #toolbar-menubar[autohide="true"] ~ #TabsToolbar .titlebar-buttonbox-container,
#main-window[tabsintitlebar][sizemode="fullscreen"] #navigator-toolbox #PanelUI-button,
#main-window #TabsToolbar #window-controls {
  display: none !important;
}

/* hide non-required items */
/*#TabsToolbar .private-browsing-indicator,*/
#TabsToolbar #window-controls,
#TabsToolbar *[type="caption-buttons"],
#TabsToolbar *[type="pre-tabs"],
#TabsToolbar *[type="post-tabs"] {
  display: none !important;
}

/* adjust private mode icon position */
@media (-moz-os-version:windows-win10), (-moz-os-version:windows-win8), (-moz-os-version:windows-win7) {
	#main-window[privatebrowsingmode=temporary]:not([inDOMFullscreen="true"]) #TabsToolbar .private-browsing-indicator {
	  position: fixed !important;
	  top: 0 !important;
	  right: 130px !important;
	  visibility: visible !important;
	  display: block !important;
	}
	#main-window[privatebrowsingmode=temporary][sizemode="maximized"]:not([inDOMFullscreen="true"]) #TabsToolbar .private-browsing-indicator {
	  top: 8px !important;
	}
}
/* adjust tabs toolbar padding */
#main-window:-moz-any([sizemode="normal"],[sizemode="maximized"],[sizemode="fullscreen"]) #navigator-toolbox #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window[tabsintitlebar]:-moz-any([sizemode="normal"],[sizemode="maximized"],[sizemode="fullscreen"]) #navigator-toolbox #toolbar-menubar[autohide="true"][inactive="true"] ~ #TabsToolbar,
#main-window:-moz-any([sizemode="normal"],[sizemode="maximized"],[sizemode="fullscreen"]) #navigator-toolbox #TabsToolbar,
#main-window[tabsintitlebar]:-moz-any([sizemode="normal"],[sizemode="maximized"],[sizemode="fullscreen"]) #navigator-toolbox #TabsToolbar {
 -moz-padding-start: 0px !important;
 -moz-margin-start: 0px !important;
}

/* hide line above navigation toolbar appearing in some cases */
#main-window:not([tabsintitlebar]) #nav-bar,
#main-window:not([tabsintitlebar]) #navigator-toolbox {
  border-top: 0 !important;
  box-shadow: unset !important;
}

/* disable Mozillas tab jumping nonsense when moving tabs */
#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;
}

/* size of new tab tabs '+' icon */
.tabs-newtab-button .toolbarbutton-icon {
  padding: 0px !important;
  margin: 0px !important;
  width: 18px !important;
  height: 18px !important;
}

/* some id!ot at Moz thought it is a great idea to add padding and margin values here */
@media (-moz-os-version:windows-win8), (-moz-os-version:windows-win7) {
  #TabsToolbar > .toolbar-items {
    padding-top: 0 !important;
	margin-top: 0 !important;
  }
}
/* 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 {
 position: absolute !important;
 bottom: 0 !important;
 width: 100vw !important;
 display: block !important;
}
#tabbrowser-tabs {
  top: 300 !important;
  width: 100vw !important;
}
#main-window:not([chromehidden*="toolbar"]) #navigator-toolbox {
	padding-bottom: calc(1px + var(--tab-min-height_tnot)) !important;
}
/* TABS: height */
:root {
 --tab-toolbar-navbar-overlap: 0px !important;
 --tab-min-height: 33px !important; /* adjust to suit your needs */
 --tab-min-height_tnot: 32px;
}
:root #tabbrowser-tabs {
 --tab-min-height: 33px !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;
	background-color: var(--toolbar-bgcolor) !important;
}
/* hide windows-controls */
#TabsToolbar #window-controls {display:none!important;}
/* move caption buttons to right of Tab bar */
#main-window[tabsintitlebar]:not([inFullscreen="true"]) #toolbar-menubar[autohide="true"] ~ #TabsToolbar .titlebar-buttonbox-container {
	position: fixed !important;
	right: 0 !important;
	top: calc(6px + var(--tab-min-height)) !important;
	display: block !important;
	visibility: visible !important;
}
#toolbar-menubar[autohide="true"] ~ #TabsToolbar {padding-right: 100px !important;}

Okulungisiwe ngu cor-el

more options

Isisombululo Esikhethiwe

You can try this change. If it doesn't work and I haven't tested the code as it mainly is code for Windows and I'm not on that platform then best is to go to Firefox CSS subreddit.

Old code:

#main-window:not([chromehidden*="toolbar"]) #navigator-toolbox {
  padding-bottom: calc(1px + var(--tab-min-height_tnot)) !important;
}

New code:

#main-window:not([chromehidden*="toolbar"]) #navigator-toolbox {
  padding-bottom: calc(1px + var(--tab-min-height_tnot)) !important;
  position: relative !important;
}

more options

cor-el

Your change WORKED!!!!

Thank you so very, very much.

Out of curiosity, is there anywhere on the web that I can learn how to read that chrome.css file?

THANK YOU, THANK YOU, THANK YOU, THANK YOU, THANK YOU.