While expanding, this combobox (maybe others also, I didn't check) passes visibly through two partly-rendered states, each for a tiny but noticeable interval. First, the combobox appears with the selected item un-highlighted and its width set incorrectly, which causes one of the elements to line-wrap; then, with the width fixed, but the selected item still un-highlighted. Two of the screenshots below demonstrate these partly rendered states.
 

Deleted: Screen Shot 2016-06-30 at 1.14.26 PM.png 27.3 KB

	Screen Shot 2016-06-30 at 1.14.26 PM.png 27.3 KB View Download

Deleted: Screen Shot 2016-06-30 at 1.14.57 PM.png 25.3 KB

	Screen Shot 2016-06-30 at 1.14.57 PM.png 25.3 KB View Download

Deleted: Screen Shot 2016-06-30 at 1.15.14 PM.png 24.8 KB

	Screen Shot 2016-06-30 at 1.15.14 PM.png 24.8 KB View Download