thanks for your reply and thanks for T4 framework
It works and then it doesn't work, very strange – it must be some cache problems with the "save configuration button" maybe a conflict, maybe a plugin order. But if you move a block around and back again – then the "save" button turns green and active in the layout settings works again.
The strangest thing is the "Block" HTML layout, which does not see the standard HTML files or the ones you save, even if the ones you save are right in the "local folder". It remembers in that session, but not when you come back.
Best regards Ulric