Invalid input message on Custom Widget

Hi all, I am building a custom widget in which I want to be able to show a Datagrid B (which is listen-to-grid/widget DataGrid A) directly beneath the clicked-upon row of DataGrid A. What I am doing, triggered by a click on a row in DataGrid A is: Adding a new row and column (one TR and one TD child) in the Datagrid A; Inserting the new row AFTER the clicked upon row; Adding the DataGrid B as a child to the newly created TD. This actually works when I stay on that page. When the new row is added and I try to click a Save or Cancel button on the page, or just try go to another page, I get the Mendix GUI error in red, stating 'Invalid input'. This probably has something to do with the fact that the insertion of the non-native TR and TD in the Mendix DataGrid widget is not being accepted in the back-end. Does anybody have a solution/workaround for this?
1 answers

I don't think Mendix supports this. The grid is managed by Mendix. Adding Rows yourself is probably not possible. You should at least create an object and link that to that row.