wait_window exception

What is the correct way to open a dialog and wait for the window
Typically I am doing the following
on a class subclassed of Toplevel

	# ----------------------------------------------------------------------
	def __init__(self, title=None,
			master=None,
			**kw):


		super().__init__(master, class_="FileDialog")
		self.transient(master)
		self.title(title)
		self.protocol("WM_DELETE_WINDOW", self.close)

                # ... all initialization.... etc...


	def show(self):
		self.focus_set()
		try:
			self.deiconify()
			self.wait_visibility()
			self.update_idletasks()
			self.grab_set()
		except tk.TclError:
			pass
		self.wait_window()
 
Unfortunately, several times when the system is not very responsive I get a traceback
report from my users like
  ...
  File \"/usr/local/flair/lib/bFileDialog.py\", line 361, in show
    self.wait_window()
  File \"/usr/lib64/python3.7/tkinter/__init__.py\", line 642, in wait_window
    self.tk.call(\'tkwait\', \'window\', window._w)
_tkinter.TclError: bad window path name \".!flair.!configdialog3.!opendialog\"


Is there the possibility that the user clicks on the "Ok" or "Cancel" button before
the code execution arrives to the wait_window(), so when it is there it gives the error message.
Or can be something else that I am missing.

Thanks in advance
Vasilis