Subsequent attempts to open modal dialog provide different results under linux

[DarkFenX]

Debian Testing x86-64
Xorg, GNOME 3 with standard theme, 3840x2160 with 200% UI scaling
Python 3.7.2
wxPython version: 4.0.4 (wxWidgets 3.0.4) from debian repos

(i think this is xorg-specific or UI-scaling specific bug which is not reproducible under wayland with full HD, but will check only later)

from time import sleep

import wx


class MainFrame(wx.Frame):

   def __init__(self):
       wx.Frame.__init__(self, None, wx.ID_ANY, 'test')
       self.Maximize()
       self.Show()
       self.showModal()

   def showModal(self):
       dlg = ModalDialog(self)
       dlg.ShowModal()
       dlg.Destroy()
       sleep(1)
       dlg = ModalDialog(self)
       dlg.ShowModal()
       dlg.Destroy()


class ModalDialog(wx.Dialog):

   def __init__(self, parent):
       wx.Dialog.__init__(self, parent, id=wx.ID_ANY, title="Dialog", size=(-1, -1), style=wx.DEFAULT_DIALOG_STYLE)
       mainSizer = wx.BoxSizer(wx.VERTICAL)

       radio1 = wx.RadioButton(self, wx.ID_ANY, 'radio1', style=wx.RB_GROUP)
       mainSizer.Add(radio1, 0, wx.EXPAND | wx.ALL, 5)

       cbSizer1 = wx.BoxSizer(wx.VERTICAL)
       checkbox11 = wx.CheckBox(self, -1, 'checkbox11')
       cbSizer1.Add(checkbox11, 0, wx.EXPAND | wx.TOP | wx.BOTTOM, 3)
       mainSizer.Add(cbSizer1, 0, wx.EXPAND | wx.LEFT, 20)

       radio2 = wx.RadioButton(self, wx.ID_ANY, 'radio2')
       mainSizer.Add(radio2, 0, wx.EXPAND | wx.ALL, 5)

       cbSizer2 = wx.BoxSizer(wx.VERTICAL)
       checkbox21 = wx.CheckBox(self, -1, 'checkbox21')
       cbSizer2.Add(checkbox21, 0, wx.EXPAND | wx.TOP | wx.BOTTOM, 3)
       checkbox22 = wx.CheckBox(self, -1, 'checkbox22')
       cbSizer2.Add(checkbox22, 0, wx.EXPAND | wx.TOP | wx.BOTTOM, 3)
       checkbox23 = wx.CheckBox(self, -1, 'checkbox23')
       cbSizer2.Add(checkbox23, 0, wx.EXPAND | wx.TOP | wx.BOTTOM, 3)
       mainSizer.Add(cbSizer2, 0, wx.EXPAND | wx.LEFT, 20)

       buttonSizer = self.CreateButtonSizer(wx.OK | wx.CANCEL)
       if buttonSizer:
           mainSizer.Add(buttonSizer, 1, wx.EXPAND | wx.ALL, 5)
       self.SetSizer(mainSizer)
       self.Fit()
       self.Center()

app = wx.App(False)
mf = MainFrame()
app.MainLoop()

First dialog:

Spam in console:

(wxtest.py:16896): Gtk-WARNING **: 21:28:50.575: for_size smaller than min-size (2 < 14) while measuring gadget (node check, owner GtkCheckButton)

(wxtest.py:16896): Gtk-WARNING **: 21:28:50.575: Negative content height -3 (allocation 1, extents 2x2) while allocating gadget (node checkbutton, owner GtkCheckButton)

(wxtest.py:16896): Gtk-WARNING **: 21:28:50.575: for_size smaller than min-size (0 < 14) while measuring gadget (node check, owner GtkCheckButton)

(wxtest.py:16896): Gtk-WARNING **: 21:28:50.575: Negative content height -2 (allocation 0, extents 1x1) while allocating gadget (node check, owner GtkCheckButton)

(wxtest.py:16896): Gtk-WARNING **: 21:28:50.575: Negative content height -9 (allocation 1, extents 5x5) while allocating gadget (node button, owner GtkButton)

(wxtest.py:16896): Gtk-WARNING **: 21:28:50.575: Negative content height -9 (allocation 1, extents 5x5) while allocating gadget (node button, owner GtkButton)

(wxtest.py:16896): Gtk-WARNING **: 21:28:50.616: for_size smaller than min-size (2 < 14) while measuring gadget (node check, owner GtkCheckButton)

(wxtest.py:16896): Gtk-WARNING **: 21:28:50.616: Negative content height -3 (allocation 1, extents 2x2) while allocating gadget (node checkbutton, owner GtkCheckButton)

(wxtest.py:16896): Gtk-WARNING **: 21:28:50.616: for_size smaller than min-size (0 < 14) while measuring gadget (node check, owner GtkCheckButton)

(wxtest.py:16896): Gtk-WARNING **: 21:28:50.616: Negative content height -2 (allocation 0, extents 1x1) while allocating gadget (node check, owner GtkCheckButton)

(wxtest.py:16896): Gtk-WARNING **: 21:28:50.616: Negative content height -9 (allocation 1, extents 5x5) while allocating gadget (node button, owner GtkButton)

Second dialog:

Console spam:

(wxtest.py:16896): Gtk-WARNING **: 21:30:28.778: for_size smaller than min-size (2 < 14) while measuring gadget (node check, owner GtkCheckButton)

(wxtest.py:16896): Gtk-WARNING **: 21:30:28.778: Negative content height -3 (allocation 1, extents 2x2) while allocating gadget (node checkbutton, owner GtkCheckButton)

(wxtest.py:16896): Gtk-WARNING **: 21:30:28.778: for_size smaller than min-size (0 < 14) while measuring gadget (node check, owner GtkCheckButton)

(wxtest.py:16896): Gtk-WARNING **: 21:30:28.778: Negative content height -2 (allocation 0, extents 1x1) while allocating gadget (node check, owner GtkCheckButton)

(wxtest.py:16896): Gtk-WARNING **: 21:30:28.778: Negative content height -9 (allocation 1, extents 5x5) while allocating gadget (node button, owner GtkButton)

(wxtest.py:16896): Gtk-WARNING **: 21:30:28.778: Negative content height -9 (allocation 1, extents 5x5) while allocating gadget (node button, owner GtkButton)

(wxtest.py:16896): Gtk-WARNING **: 21:30:28.827: Negative content height -9 (allocation 1, extents 5x5) while allocating gadget (node button, owner GtkButton)

(wxtest.py:16896): Gtk-WARNING **: 21:30:28.827: Negative content height -9 (allocation 1, extents 5x5) while allocating gadget (node button, owner GtkButton)

(wxtest.py:16896): Gtk-WARNING **: 21:30:28.861: Negative content height -9 (allocation 1, extents 5x5) while allocating gadget (node button, owner GtkButton)

(wxtest.py:16896): Gtk-WARNING **: 21:30:28.861: Negative content height -9 (allocation 1, extents 5x5) while allocating gadget (node button, owner GtkButton)

(wxtest.py:16896): Gtk-WARNING **: 21:30:28.896: Negative content height -9 (allocation 1, extents 5x5) while allocating gadget (node button, owner GtkButton)

(wxtest.py:16896): Gtk-WARNING **: 21:30:28.896: Negative content height -9 (allocation 1, extents 5x5) while allocating gadget (node button, owner GtkButton)

(wxtest.py:16896): Gtk-WARNING **: 21:30:28.927: Negative content height -9 (allocation 1, extents 5x5) while allocating gadget (node button, owner GtkButton)

(wxtest.py:16896): Gtk-WARNING **: 21:30:28.927: Negative content height -9 (allocation 1, extents 5x5) while allocating gadget (node button, owner GtkButton)

(wxtest.py:16896): Gtk-WARNING **: 21:30:28.960: Negative content height -9 (allocation 1, extents 5x5) while allocating gadget (node button, owner GtkButton)

(wxtest.py:16896): Gtk-WARNING **: 21:30:28.960: Negative content height -9 (allocation 1, extents 5x5) while allocating gadget (node button, owner GtkButton)

(wxtest.py:16896): Gtk-WARNING **: 21:30:28.979: Negative content height -9 (allocation 1, extents 5x5) while allocating gadget (node button, owner GtkButton)

(wxtest.py:16896): Gtk-WARNING **: 21:30:28.979: Negative content height -9 (allocation 1, extents 5x5) while allocating gadget (node button, owner GtkButton)

If I change proportion attribute to 1, it looks better but still space below ok/cancel is different:

Expected result:
I am unsure what would be appropriate behavior. But i would expect dialog to fit all the controls by default in their full scale (so like 2nd screenshot but non-shrinked buttons).

[DarkFenX]

Test results from another PC:

Debian Testing x86-64
GNOME 3 with standard theme, 1920x1080
Python 3.7.2
wxPython version: 4.0.4 (wxWidgets 3.0.4) from debian repos

Wayland 1st:

Wayland 2nd:

Xorg 1st:

Xorg 2nd:

So, this seems to be xorg-specific issue.