https://en.wikipedia.beta.wmflabs.org/wiki/Special:GlobalPreferences#mw-prefsection-editing has the following text "Make this setting global" but no checkbox and then "Select all" with a checkbox. So, what does the checkbox do?
Topic on Help talk:Extension:GlobalPreferences
Good question! The checkbox will select all the checkboxes below it (or unselect them, if it's unselected).
Just today actually we're rejigging this to be just a checkbox with "Select all options below to be global". Check out some screenshots at phab:T188358#4004802.
Do you think this will make it clearer?
No, because it sounds like it not only makes them global but also enables them all. Maybe it would be clearer to have a checkbox "Make all selected preferences apply globally" for this function?
Can we possibly just omit the "Make this setting global" check box, I mean if someone navigates to Special:GlobalPreferences then it's obvious that he wants to makes the preferences global and not local
You mean not have anything at the top at all?
Is it obvious that the left-side checkboxes are the things that enable each pref globally? (I think it is, but I've been looking at this form for too long!) Oh, and if you hover over those left checkboxes you do get a popup that says 'make this setting global'; that might help too, along with the background colour highlight.
And also, is it obvious that the checkbox at the top is just a convenience toggle thing that turns the ones below on and off and doesn't do anything in and of itself? And that it only applies to the current preferences tab?
I happy with whatever the consensus is! :)