Widget Styles Window Doesn’t Load

Hi All – Ive had a mystery when editing a visual editor window where I see the windows for editing the test/content however the widget styles side screen on the right fails to show, I get the circle round and round only. The editor works fine all quite normal, obviously should i wish to change attributes/layout/design then no dice. My attempts to find solution have been to deactivate all the plugins and then activate only pagebuilder and then tinymce returning to the page still has same problem. Then i’ve changed the theme to another different theme with similar layout but still the same problem. As last resort I changed the Enable full-height editor and distraction-free functionality on/off and I must be getting close as I can switch this option on / off so that the widget styles appears and then the editing window has the round and round circle that never loads the window. Has anyone come across this problem and if so can offer a fix to this annoyance.. The website is fine otherwise and still can be worked on but there must be an error somewhere and I am most curious. I have a test site I play with that has this issue in the link below – where you can see three images of the problems.

URL: http://sophieallendesigns.co.uk/builder/