Fix selection mode aftzer removal of the local context in OCCT 7.3.0.

thanks @VASIMRLJJ
- see https://dev.opencascade.org/content/local-context-removal
- and #729

Author: EmJay276

src/Display/OCCViewer.py

@@ -627,6 +627,7 @@ def Pan(self, dx, dy):
         self.View.Pan(dx, dy)
 
     def SetSelectionMode(self, mode=None):
+        self.Context.Deactivate()
         topo_level = next(modes)
         if mode is None:
             self.Context.Activate(AIS_Shape_SelectionMode(topo_level), True)