Not working with Fixed Widget

Hi, thanks for the plugin. The basics work, but it seems incompatible with the fixed widget plugin:
https://ww.wp.xz.cn/plugins/q2w3-fixed-widget/

Not sure why as all of my otehr widgets (standard and custom) do have a checkbox to make it fixed or not, but the flexipages widget does not.

Can you check and maybe update it?
Cheers,
Bike

https://ww.wp.xz.cn/plugins/flexi-pages-widget/