It's ok
I am not the best guy explaining stuff in english
Those two ID's are separate tags and you can have them both in your code
ID="ToolBarButton_MainMenu"
is a tag for the new menu thing. it used to be a regular button. You can hide it by replacing width and height values to "1".
ID="ToolbarButton_Slot_1"
is complitely a new tag. this is basically the old ToolBarButton_MainMenu. I'll try to rewrite the notes how to replace these buttons.