OS X: Overlay scrollbar behaviour is not true to OS system preferences when using an external mouse

The "overlay_scroll_bars" setting in Sublime is not true to the OS X system preference value 'When scrolling', when using an external mouse on a Mac laptop. With values 'system' or 'enabled', the scrollbars will show as overlayed when scrolling with the touchpad on the laptop, however if scrolling with an external mouse (I use a Logitech), the scroll bars do not show. With this mouse I can only get the scrollbars to show when setting the value to 'disabled' or using the OS system preference values 'Automatically based on mouse or trackpad' or 'Always'.

The behaviour to show the scrollbars when scrolling with an external mouse on OS setting 'When scrolling' works as it should in other apps. It would be great to get this working as it should in Sublime!