Just had an idea for how to fix Mozilla Bug 225088 and satisfy both sides. For icons only mode, set the button to a deck or stack or whatever it’s called so the label is layered over the icon, and have the text centered on the button so you can still see the text, but it doesn’t take up extra space next to the button as it would in icons+text mode which would act normally. It would need a new, slightly larger icon graphic with a “hollow” center, but that might be good, as it would then more closely match the size of the rest of the toolbar buttons. The one big drawback i can think of is it wouldn’t localize well; “go” in other languages is likely more than just two letters.