Hello!

I'm using a custom script made by MrOtherGuy that serves to hide the whole toolbox. The code is this: https://github.com/MrOtherGuy/firefox-csshacks/blob/master/chrome/autohide_toolbox.css

/* Source file https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/autohide_toolbox.css made available under Mozilla Public License v. 2.0
See the above repository for updates as well as full license text. */

/* Hide the whole toolbar area unless urlbar is focused or cursor is over the toolbar
 * Dimensions on non-Win10 OS probably needs to be adjusted.
 */

:root{
  --uc-autohide-toolbox-delay: 200ms; /* Wait 0.1s before hiding toolbars */
  --uc-toolbox-rotation: 82deg;  /* This may need to be lower on mac - like 75 or so */
}

:root[sizemode="maximized"]{
  --uc-toolbox-rotation: 88.5deg;
}

u/media  (-moz-platform: windows){
  :root:not([lwtheme]) #navigator-toolbox{ background-color: -moz-dialog !important; }
}

:root[sizemode="fullscreen"],
:root[sizemode="fullscreen"] #navigator-toolbox{ margin-top: 0 !important; }

#navigator-toolbox{
  --browser-area-z-index-toolbox: 3;
  position: fixed !important;
  background-color: var(--lwt-accent-color,black) !important;
  transition: transform 82ms linear, opacity 82ms linear !important;
  transition-delay: var(--uc-autohide-toolbox-delay) !important;
  transform-origin: top;
  transform: rotateX(var(--uc-toolbox-rotation));
  opacity: 0;
  line-height: 0;
  z-index: 1;
  pointer-events: none;
  width: 100vw;
}
:root[sessionrestored] #urlbar[popover]{
  pointer-events: none;
  opacity: 0;
  transition: transform 82ms linear var(--uc-autohide-toolbox-delay), opacity 0ms calc(var(--uc-autohide-toolbox-delay) + 82ms);
  transform-origin: 0px calc(0px - var(--tab-min-height) - var(--tab-block-margin) * 2);
  transform: rotateX(89.9deg);
}
#mainPopupSet:has(> [panelopen]:not(#ask-chat-shortcuts,#selection-shortcut-action-panel,#chat-shortcuts-options-panel,#tab-preview-panel)) ~ toolbox #urlbar[popover],
#navigator-toolbox:is(:hover,:focus-within,[movingtab]) #urlbar[popover],
#urlbar-container > #urlbar[popover]:is([focused],[open]){
  pointer-events: auto;
  opacity: 1;
  transition-delay: 33ms;
  transform: rotateX(0deg);
}
#mainPopupSet:has(> [panelopen]:not(#ask-chat-shortcuts,#selection-shortcut-action-panel,#chat-shortcuts-options-panel,#tab-preview-panel)) ~ toolbox,
#navigator-toolbox:has(#urlbar:is([open],[focus-within])),
#navigator-toolbox:is(:hover,:focus-within,[movingtab]){
  transition-delay: 33ms !important;
  transform: rotateX(0);
  opacity: 1;
}
/* This makes things like OS menubar/taskbar show the toolbox when hovered in maximized windows.
 * Unfortunately it also means that other OS native surfaces (such as context menu on macos)
 * and other always-on-top applications will trigger toolbox to show up. */
u/media (-moz-bool-pref: "userchrome.autohide-toolbox.unhide-by-native-ui.enabled"),
       -moz-pref("userchrome.autohide-toolbox.unhide-by-native-ui.enabled"){
  :root[sizemode="maximized"]:not(:hover){
    #navigator-toolbox:not(:-moz-window-inactive),
    #urlbar[popover]:not(:-moz-window-inactive){
      transition-delay: 33ms !important;
      transform: rotateX(0);
      opacity: 1;
    }
  }
}

#navigator-toolbox > *{ line-height: normal; pointer-events: auto }

/* Don't apply transform before window has been fully created */
:root:not([sessionrestored]) #navigator-toolbox{ transform:none !important }

:root[customizing] #navigator-toolbox{
  position: relative !important;
  transform: none !important;
  opacity: 1 !important;
}

#navigator-toolbox[inFullscreen] > #PersonalToolbar,
#PersonalToolbar[collapsed="true"]{ display: none }

/* This is a bit hacky fix for an issue that will make urlbar zero pixels tall after you enter customize mode */
#urlbar[breakout][breakout-extend] > .urlbar-input-container{
  padding-block: calc(min(4px,(var(--urlbar-container-height) - var(--urlbar-height)) / 2) + var(--urlbar-container-padding)) !important;
}

/* Uncomment this if tabs toolbar is hidden with hide_tabs_toolbar.css */
 /*#titlebar{ margin-bottom: -9px }*/

/* Uncomment the following for compatibility with tabs_on_bottom.css - this isn't well tested though */
/*
#navigator-toolbox{ flex-direction: column; display: flex; }
#titlebar{ order: 2 }
*/

It works great but what I'd like to do is to make it so that when I click a tab and drag it to change its place in the tabbar nothing disappears, this is because when I click and drag a tab the toolbox disappears and the tab goes to a new windows when I let go of it.

Thanks a lot!