wxGUI: fix Gtk warnings when switching to 3D view (since https://trac.osgeo.org/grass/changeset/50013)

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@51699 15284696-431f-4ddb-bdfa-cd5b030d7da7

gui/wxpython/gui_core/widgets.py

@@ -98,7 +98,7 @@ class GNotebook(FN.FlatNotebook):
 
 class ScrolledPanel(SP.ScrolledPanel):
     """!Custom ScrolledPanel to avoid strange behaviour concerning focus"""
-    def __init__(self, parent, style = wx.TAB_TRAVERSAL | wx.SUNKEN_BORDER):
+    def __init__(self, parent, style = wx.TAB_TRAVERSAL):
         SP.ScrolledPanel.__init__(self, parent = parent, id = wx.ID_ANY, style = style)
 
     def OnChildFocus(self, event):