wrong location when width and height set to 'auto'

[joprice]

I'm trying to add a tooltip to a floating button in the corner of the screen. When providing width and height 'auto', the relatively short text remains on one line, instead of spanning to two (the real text will be a bit longer as well), and the caret is in the right place, but the popover jumps to the left of the screen.

Is there a way to get the width to be constrained by the intrinsic size of the children, and have overlay correctly positioned?