Modify copy_widget to allow non-visible widgets

Author: RedFantom

ttkwidgets/utilities.py

@@ -60,10 +60,12 @@ def copy_widget(widget, new_parent, level=0):
             temp = widget.place_info()
             del temp['in']
             rv.place(**temp)
-        else:  # if geometry manager is pack
+        elif widget.pack_info():  # if geometry manager is pack
             temp = widget.pack_info()
             del temp['in']
             rv.pack(**temp)
+        else:  # No geometry manager configured
+            pass
     level += 1
 
     if widget.pack_slaves():  # subwidgets are using the pack() geometry manager