Now, spacing. So, toolbars are supposed to have 6px padding on all sides, right? Well, that's not entirely true. It only has side padding, while top/bottom padding is instead margins on each button, each entry, each switch and each separator. And then we undo it for popovers, so that buttons like in Epiphany's menu don't have extra padding.
This may sound ridiculous, and honestly it is, but the reason is these 3 cases.
Honestly, we should probably just get rid of all 3:
- view switchers can just be always wide in header bars, nobody really likes the narrow layout there anyway. And view switcher bars - we can just make them taller and use the regular padding
- calendar and logs should be redesigned, they look broken anyway
Now, why does it matter for collapsing spacing? Well, undoing those margins for buttons, entries, separators and switches in this particular case would make that css even more complex than it already is, and basically unmaintainable. If it was just padding on the toolbar we could do it easily, but with that part in mind... Yeah, not happening.