Python GX: get_user_input with output of project_grids

I have a get_user_input dialog that prompts the user to pick an existing grid from the project:

        # ask the user to select a grid
        grid_file = gxproj.get_user_input(title='Specify existing TMI grid',
                                        prompt='TMI grid:',
                                        kind='list',
                                        items=project.project_grids,
                                        default=default_grid)

The list usually works fine, but when I run it in a project with a lot of grids (maybe 100?) it displays the first 15 grids, and then only a few characters of the 16th grid path, and no more. Is there a limit to how many items can be included in the pick-list or how many characters?