Adding ToTabPane on Pyramid create lots of child elements

[LANDAISB]

I try to add a ToTabPane on Pyramid.

Maybe two probelms :

1. It creates a ToTabPane with a body (ToPane) and a header (ToTabPaneHeader). The header contains 3 childs ToPane and one of them contains also 3 childs (ToElement and ToPane).
   It seems it's a lot of childs/subchilds, is it normal ?

2. If I save and re-open Pyramid, it duplicates all childs under each ToTabPane

[Nyan11]

The bug is present because the ToTabPane is a subclass of ToPane, and in Toplo-Serialization i decided to serialize the children of ToPane.

But it does not make sense to serialize the children of ToTabPane, we should only serialize the "tabs" and not the children

[Nyan11]

I fix the serialization, it should not recreate the elements infinitly.
But ToTabPane uses BlockClosure and it is complicated to serialized BlockClosure.

Currently the ToTabPane will try to serialize the ToTab.
I can deactivate this functionnality if needed