Notebook - what event to catch

[Werner F. Bruhin]

I have a notebook with 8 pages which each shows some data from a database.

If there is much data the loading is a bit slow and I would like to 
obtimize it.

I was thinking of just getting the data from the database of the page 
which is actually shown/active.

The pages are wx.Panel's and I thought of using wx.EVT_SET_FOCUS but 
that doesn't seem to fire when I click on particular tab on the notebook.

I got it mostly working with a combination of checking 
panel.IsShownOnScreen() and notebook.EVT_FLATNOTEBOOK_PAGE_CHANGING but 
I wonder if there are other alternatives.

Best regards
Werner