I have a form (wx.Frame) in which the widest element is the toolbar (created with toolbar = self.CreateToolbar() and toolbar.Realize()). I want the width of the form to be such that every toolbar item is shown. I don't see the toolbar changing after creation, but I'd prefer if that could be handled. Any suggestions?
(I'm running Python 2.7, with non-Phoenix wxPython)
You'll have to figure out what the width of a toolbar item is. Then you can take that number and multiply it by the number of toolbar items and set the frame's size appropriately. 
Then when you add or remove a toolbar item, part of that process will be to update the size of the frame (SetSize()). You will probably need to call the frame's Layout() method after adding/removing the widget. You may also need to call Refresh().
Set width of wxPython Frame based on toolbar width