v0.16.3

This release reverts a change in Combobox that, while addressing the issue in #755, was not tested thoroughly enough and caused a regression where in some cases the popover doesn't open until the user presses the down or up key after initial input. If you updated to v0.16.3 specifically as a workaround to this issue, I apologize! A new fix is in progress for the next release, and I'm working to ensure it's a bit more battle tested this time around.