firefox_full_sceen_mode_show_bookmarks

follow this guide https://support.mozilla.org/en-US/questions/1212156


more specifically

create chrome directory under ~/.mozilla/firefox/<profile>/

create css file userChrome.css under chrome directory


/*
   Override hiding of Bookmarks Toolbar in F11 full screen
   when you roll down the tabs/main toolbar 
*/
#navigator-toolbox[inFullscreen="true"] #PersonalToolbar {
  visibility: unset !important;
}


profile can be viewed under help->more trouble shooting -> basics



However, so far it still dosen't work

see https://winaero.com/enable-loading-userchrome-css-usercontent-css-firefox/

about:config

toolkit.legacyUserProfileCustomizations.stylesheets = true