How to remove "Open all in tabs"

[Kjaeremandag]

I've tried this but does not work, is there any way to remove it?
.openintabs-menuitem,
.bookmarks-actions-menuseparator {
display: none !important;
}

[Kjaeremandag]

No one?

[Mopslik]

For me works this:

.openintabs-menuseparator,
.openintabs-menuitem,
.bookmarks-actions-menuseparator
{ display: none !important; }

[Kjaeremandag]

Thank you for the reply, i was making that change to userChrome, so today i tried to put it in leptonChrome and it worked!

[nademin]

Full How to guide:

Code from Mozilla Support forum plus couple additions from Mopslik's solution

Type about:config in the address bar and press Enter.
Search for toolkit.legacyUserProfileCustomizations.stylesheets and toggle it to true. This setting is required for userChrome.css to work

Type about:support in the address bar and press Enter.
Look for the Application Basics section.
Click on Open Profile Folder. This will open the folder where Firefox stores your user data.

In the Profile Folder, create a new folder and name it chrome (it may be already exist)
Inside the chrome folder, create a new blank file named userChrome.css (make sure that it is NOT userChrome.css.txt)
Place this code inside userChrome.css and restart your browser for the changes to take effect

/* Hide Open All In Tabs Sub-Menu */
@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* Only needed once! */
#PlacesToolbarItems .openintabs-menuitem,
#PlacesToolbarItems .openintabs-menuseparator,
#PlacesToolbarItems .bookmarks-actions-menuseparator,
#placesContext>menuitem[id="placesContext_openContainer:tabs"],
#placesContext>menuitem[id="placesContext_openContainer:tabs"]:not([hidden])+menuitem+#placesContext_openSeparator {visibility:collapse!important}