I want to build an app for making UML diagrams. For visibility problems, I wish I could move classes using the mouse.
So here is my problem :
Do you know how can I drag and drop a widget in a canvas using wxPython ?
Found some things about ogl, but sound strange to me ... 
Thx guys
Take a look at the FloatCanvas sample in the wxPython demo.  There is also a sample for the OGL package there.  Either, or both of those would likely be suitable for diagrams depending on your needs.
wxpython self made widget and drag and drop it in a canvas