Don’t handle text editor focus when it already has focus

src/text-editor-element.coffee

@@ -89,7 +89,11 @@ class TextEditorElement extends HTMLElement
     React.unmountComponentAtNode(this)
     @component = null
 
-  focused: ->
+  focused: (event) ->
+    if @hasFocus()
+      event.stopPropagation()
+      return
+
     if @component?
       @component.focused()
     else