Python Add-in tool

Hello,

I am working on ArcMap and I would like to display something (a shape or openning a MessageBox) when I click on the map. I need to use "onMouseDownMap()" in python and I need to create a toolbar with a special tool to execute what I want. (I use Python Add-in Wizard)

I followed ArcGIS Help to do this and in the end, my new toolbar doesn't appear on ArcMap and I really don't know why. I tried to customize my toolbar and find the new I've just created but it doesn't exist. Do you know why?

Thank you!