[Bug] wxGUI/nviz: an error message is printed during docking undocked 3D view window

[tmszi]

Describe the bug

An error message is printed during docking undocked 3D view window.

To reproduce

1. Launch wxGUI
2. Display some raster elevation map d.rast elevation
3. Switch 2D view to the 3D view
4. Hit (Un)dock (undocking) button from the map display toolbar
5. Hit (Un)dock (docking) button from the map display toolbar window
6. See error message

Traceback (most recent call last):
  File "/usr/lib64/grass86/gui/wxpython/nviz/mapwindow.py",
line 441, in OnSize
    self.SetCurrent(self.context)
    ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
wx._core.wxAssertionError: C++ assertion ""xid"" failed at /
var/tmp/portage/x11-libs/wxGTK-3.2.8.1-r2/work/wxWidgets-
3.2.8.1/src/unix/glx11.cpp(584) in SetCurrent(): window must
be shown

Expected behavior

No error message should be printed during docking undocked 3D view window.

System description

• Operating System: all
• GRASS version: 8.6.0dev, 8.5.0

Additional context

According my debug info, during docking undocked 3D view window is called

grass/gui/wxpython/main_window/notebook.py

Line 143 in c2ccb36

self.AddPage(page, frame.GetTitle())

which trigger wx.EVT_SIZE event with OnSize() method handler (problematic is code line no. 428)

grass/gui/wxpython/nviz/mapwindow.py

Lines 420 to 428 in c2ccb36

	def OnSize(self, event):
	size = self.GetClientSize()
	context = self.context if CheckWxVersion(version=[2, 9]) else self.GetContext()
	if self.size != size and context:
	Debug.msg(
	3, "GLCanvas.OnSize(): w = %d, h = %d" % (size.width, size.height)
	)
	if CheckWxVersion(version=[2, 9]):
	self.SetCurrent(self.context)

before the window is displayed.