ok . Changed from the Leave Event to the Validated Event , and the messageBox just fires the once.Unless someone jumps in with a reson 'NOT' to use the Validated event, I'll use this in future.

I have a TextBox on a form , and on the Leave event I have code to call the BrowseLookup and am getting some unexpected behaviour. With some experimenting, i notice that this seems to be standard .net behaviour and happens even if a messagebox.show  is called from the Leave event.

e.g.

If I have on the Leave event of a textBox:   Messagebox.Show("This is a test") , this messagebox displays once.

if I have : MessageBox.Show("This is a test");   followed by This.MyOtherControl.Focus(), the Messagebox fires twice. The fact that I have a Focus seems to be firing the 'Leave' event a second time.

I would need to do this type of thing quite regulalry  i.e. on leaving a control, DO SOMETHING and then set focus to another control. Is the 'Leave' event the best time to do this or is there some other way round the Leave event firing twice ?