This article will walk you through my mistake and show you two solutions to the issue.

Here is an example of what I did originally:

<pre class="EnlighterJSRAW" data-enlighter-language="python">
# simple_note.py

import random
import wx

class TabPanel(wx.Panel):

def __init__(self, parent, name):
""""""
super().__init__(parent=parent)
self.name = name

colors = ["red", "blue", "gray", "yellow", "green"]
self.SetBackgroundColour(random.choice(colors))

btn = wx.Button(self, label="Press Me")
sizer = wx.BoxSizer(wx.VERTICAL)
sizer.Add(btn, 0, wx.ALL, 10)
self.SetSizer(sizer)

class DemoFrame(wx.Frame):
"""
Frame that holds all other widgets
"""

def __init__(self):
"""Constructor"""
super().__init__(None, wx.ID_ANY,
"Notebook Tutorial",
size=(600,400)
)
panel = wx.Panel(self)

self.notebook = wx.Notebook(panel)
self.notebook.Bind(wx.EVT_NOTEBOOK_PAGE_CHANGED, self.on_tab_change)
tabOne = TabPanel(self.notebook, name='Tab 1')
self.notebook.AddPage(tabOne, "Tab 1")

tabTwo = TabPanel(self.notebook, name='Tab 2')
self.notebook.AddPage(tabTwo, "Tab 2")

sizer = wx.BoxSizer(wx.VERTICAL)
sizer.Add(self.notebook, 1, wx.ALL|wx.EXPAND, 5)
panel.SetSizer(sizer)
self.Layout()

self.Show()

def on_tab_change(self, event):
# Works on Windows and Linux, but not Mac
current_page = self.notebook.GetCurrentPage()
print(current_page.name)
event.Skip()