#10 Layout error after page drag between notebooks

[arst]

First a side-remark:

It is not possible (AFAIK) to track page drag between notebooks on current wxFlatNotebook. I submitted a patch here which fully solves this some 6 months ago.

Without a proper notification event on dragging pages between notebooks, the feature is less useful.

Main issue - Notebook page split in 2
The problem occurs when dragging windows between two notebooks AND when dropping it on a position before the selected index in target notebook.

Consider:
Notebook1: Source in page drag
Notebook2: Target in page drag. Selected page is 4.
From NB1 we drop a page on position 1 in NB2.
Then the layout of NB2 is messed up and remains so until program shutdown.

I reproduced it in the sample application. Screenshot included.

Regards
// ATS.

[arst]

snapshot