[Closed] Custom attributes floater doesn't remember checkbox state

I’ve scripted a custom attributes floater on a attributes holder modifier. It contains some spinners and a checkbox. The default state for the checkbox is false, however when I have it checked and deselect and reselect the object containing the floater the checkbox is unchecked again.

The spinner values are remembered so not sure what’s I’m doing wrong here.
Hope someone can help me.