Conflict with Radio Buttons for Taxonomies

Hi and thanks for the fantastic plugin!

I’m having an issue with the latest version. I think it might be conflicting with Radio Buttons for Taxonomies (https://wordpress.org/plugins/radio-buttons-for-taxonomies/). When both plugins are active, I can see the taxonomy in question with radio buttons in the Flexible Posts Widget, but my selection won’t save. It keeps reverting to ‘none’.

This is happening on a site running wp 4.2.2 on php 5.4.4.

Thanks for your help!

https://wordpress.org/plugins/flexible-posts-widget/