Checkbox in a flex does not shrink to respect other elements flex grow

[vegegoku]

Having a code like this does not let the checkbox shrink to make the grow element to actually grow and take the full sspace

div().addCss(dui_flex, dui_gap_2)
                .appendChild(CheckBox.create().addCss(dui_w_auto))
                .appendChild(TextBox.create("Text box").addCss(dui_grow_1));

and result to something like this

The result should be something like this