ScrolledPanel Difference on Mac vs Windows

wxPython Users
#1

I’ve got a fairly complex frame with panels and sizers, including a ScrolledPanel. The issue is that on Mac I can see the scroll bar, but on Windows it simply doesn’t work.

The code is the same, see below:

import wx
import wx.lib.scrolledpanel

class MyFrame(wx.Frame):
    def __init__(self, *args, **kw):
        super(MyFrame, self).__init__(*args, **kw, size=app_size)

        self._panel = wx.Panel(self)
        self._vbox = wx.BoxSizer(wx.VERTICAL)
        self._sb = wx.StaticBox(self._panel)
        self._sbs = wx.StaticBoxSizer(self._sb, orient=wx.VERTICAL)
        self._panel.SetSizer(self._sbs)

        # buttons
        self._h_box_buttons = wx.BoxSizer(wx.HORIZONTAL)
        self._quitButton = wx.Button(self, label='Quit')
        self._h_box_buttons.Add(self._quitButton, flag=wx.ALIGN_LEFT)
        self._quitButton.Bind(wx.EVT_BUTTON, self.on_close)

        self._vbox.Add(self._panel, proportion=1, flag=wx.ALL|wx.EXPAND, border=5)
        self._vbox.Add(self._h_box_buttons,
            flag=wx.ALIGN_CENTER|wx.TOP|wx.BOTTOM|wx.ALL|wx.EXPAND, border=10)

        self.SetSizer(self._vbox)

        self.InitUI()

    def InitUI(self):
        msg = "Welcome to my scroll test!"
        self.showMessage(msg)

        self.s_p = wx.lib.scrolledpanel.ScrolledPanel(self, -1, size=(575, 100), style=wx.SIMPLE_BORDER)
        self.s_p.SetupScrolling()
        self.s_sizer = wx.BoxSizer(wx.VERTICAL)
        self.s_p.SetSizer(self.s_sizer)
        self._sbs.Add(self.s_p)

        for idx in range(1, 20):
            msg = "Line: " + str(idx)
            t = wx.StaticText(self.s_p, label=msg)
            self.s_sizer.Add(t)
        msg = "That's a wrap folks..."
        self.showMessage(msg)

    def showMessage(self, msg):
        t = wx.StaticText(self._panel, label=msg)
        self._sbs.Add(t)
        self._sbs.AddSpacer(10)

    def on_close(self, e):
        self.Close(True)

# Run the program
if __name__ == "__main__":
    app = wx.App()
    app_size = (600, 700)
    ex = MyFrame(None)
    ex.Show()
    app.MainLoop()
#2

You made the ScrolledPanel be a child of self, (the frame). You probably meant to make it a child of the self._panel instead.