Button does not show up correctly...

I created the buttons in wxWidgets and wxPython with the following lines.
The codes are virtually identical, but the look and feel differs somehow.

wxWidgets:

cancelButton = new wxButton(panel, (wxWindowID)ID_CANCEL_BUTTON, wxT("Cancel"), wxDefaultPosition, wxDefaultSize, wxBU_EXACTFIT);

wxPython:

ctrlButton = wx.Button(parent=self, id=-1, label=label.decode('utf-8'), style=wx.BU_EXACTFIT)