Let me tab between the keybind options.

4chan_x.user.js

@@ -1427,6 +1427,7 @@
       return g.hiddenReplies = {};
     },
     keybind: function(e) {
+      if (e.keyCode === 9) return;
       e.preventDefault();
       e.stopPropagation();
       if ((key = keybinds.keyCode(e)) == null) return;

script.coffee

@@ -1068,6 +1068,7 @@ options =
     @textContent = "hidden: 0"
     g.hiddenReplies = {}
   keybind: (e) ->
+    return if e.keyCode is 9
     e.preventDefault()
     e.stopPropagation()
     return unless (key = keybinds.keyCode e)?