Datagrid: How to move an adorner behind a frozen column

[SokoFromNZ]

Hi everyone.

The nature of an adorner is to lay over the other controls. On a datagrid with a frozen column and an adorner on a cell of a moving column this leads to an obvious visual bug for the user:

I'm a WPF developer since 15 years ... but I cannot even think of a theoretical solution to this issue.

So I'm open to any wild ideas here :)

thanks
Soko