Actually, I've found that sometimes another icon will prevent the bar from collapsing. That is, I'll have, let's say, those three icons plus a few others. The bar will stop collapsing at those three icons. Then I'll put another in and it will prevent the bar from collapsing past it. While I've not figured out the exact method why this works, it leads me to believe that there's something specific to certain icons/shortcuts that prevents the bar from collapsing past them.