                 non_modifier_keys.splice(i, 1) 
         if non_modifier_keys.length > 1
             _log_error "META and CMD key combos cannot have more than 1 non-modifier keys", combo, non_modifier_keys
-            return true
-    return true
+            validated = false
+
+    # Tell the user if they are trying to use any
+    # combo properties that don't actually exist,
+    # but allow the combo
+    for property, value of combo
+        if _factory_defaults[property] is "undefined"
+            _log_error "The property #{property} is not a valid combo property. Your combo has still been registered."
+
+    return validated
 
 _convert_to_shifted_key = (key, e) ->
     return false unless e.shiftKey

    return valid

_validate_combo = (combo) ->
    # Warn for lack of keys
    unless combo.keys.length
        _log_error "You're trying to bind a combo with no keys."

    # Convert "meta" to either "ctrl" or "cmd"
    # Don't explicity use the command key, it breaks

    for key in combo.keys
        unless _key_is_valid key
            _log_error "Do not recognize the key \"#{key}\""
            validated = false

    # We can only allow a single non-modifier key
    # in combos that include the command key (this
