‘Apply to All sites’ option at the main site works for the currently selected role only. It’s not related to the additional modules (like ‘Widgets’) data.
Widgets, admin menu items available at different single sites may be different as single sites may have different set of activated plugins and themes. So I did not include network update feature for the additional modules from very begin. I see with time that some clients (including you) need such feature. I will add it module by module.
If you open ‘User Role Editor’ at the ‘Network Admin – Users’ you should see ‘Update Network’ button there. It opens dialog where you may add ‘Widgets’ restrictions data to the update process:
Code was written this way:
Widgets added by single site admin (superadmin) should be shown 1st. Widgets added by users should be shown below.
Could you describe in details your scenario in order I may test it myself and develop a fix if needed? What widgets you added as superadmin, what widgets as a user? What role has your non-administrator user who adds widgets (screenshot)?
I don’t have on hands a solution to block sidebars. I will check what we can do with it.