Hello,
The validation error is probably in the adorner layer and the element providing the adorner is outside the contentpane. You should report this issue to the support group. For now, you can probably retemplate the ContentPane and put an AdornerDecorator in there. We ship the default styles so you can take the default template and put the AdornerDecorator as the root element within the template (or within the border).
Thanks for the quick i reply i will try what you have suggested and and hopefully that works for now Thanks!