Management of a listbox with checkboxes

I would like to display a child window or information each time you check a checkbox in a (hierarchical) DesktopListBox. I tested “if index then” and “Select case RowTagAt()” in event “Listbox.CellAction” but each time the previously checked boxes are executed again (the windows or information are displayed again ), while I would like only the last checked box to execute. Where to put my code and how?

As far as I remember during CellAction the checkbox shows the previous state.

I solved my problem, thanks.