Worksheet Activate does not run when sheet activated using VBA

Hi

I have been using worksheet activate to change the formatting on a number of sheets and when changing sheet via a tab or ctrl + page up / page down, everything functions correctly. However if the sheet is changed via VBA the worksheet activate macro is not triggered ( I have tried this with Excel 2000 through 2007 and windows Vista and 7). I cannot find any reference to this using google and would appreciate it if anyone has come across this behaviour and has any workarounds that they could advise me of.

Regards

Jeff