Drop a Button.
Use the Font editor and try to select a font size within the pull-down list: as soon as you move mouse cursor from over the arrow to the list then the list is dismissed before you've time to select any of the values.
If you really click on the very bottom of the pull-down menu button you sometimes get it right.
This example is not the worse because for setting font size ones has also a text field and a slider.
But in many other editors used e.g. for effects there's no choice but select the value in the popup list.

It works fine on Windows and Mac.