Currently, there's no higher-level indication that a complex dialog contains one or more required fields on the tabs which are out of the editor's view, e.g. the Address and Contact details tabs below:

The editor may then click the Save changes button instantly on the active tab and probably hit an error pointing to the fact that other tabs need some input as well before saving.

For a skilled editor, we could soften this a bit by providing a visual hint next to the tab labels informing the editor that the other tab(s) need some interaction as well before saving:

I believe this could make the editing workflow smoother by eliminating the error pop-ups.