Ensure exactly 1 selcted row in data grid

Hi all, Short question: How can I ensure that always exactly one row in a data grid is selected? I enabled the functionality that the first row is selected by default. But I want to prevent that the user can unselect the first row. The user should only be able to select another row and by clicking on an already selected row, nothing should change.   Any ideas highly appreciated
1 answers

In the Datagrid properties set the selection mode to "Single selection and maintain”. 

That will do this: "The user can select one item at a time by clicking on it. Users cannot deselect an item. By default the first item will be selected and removing a selected item will autoselect a subsequent item.”, which seems to be your requirement.