But full support is relatively recent and for some reason, it doesn't behave like a typical editable combo box: it looks like a regular text field until you interact with it, while most GUI toolkits display them as a text field within a combo box frame, with the down arrow button always visible. Unless there is some special styling, why not use the OS default look and feel?

Still a step in the good direction, but why so late? and why the nonstandard behavior?