I see this term used a lot in properties and methods. Not sure what it means. Any help would be appreciated.
yes, though focus is usually used just for shifting the focus, you would then hit enter to trigger the button or open the menu.
you know how you can use the tab key to navigate elements in a window or the desktop environment? You are using the tab key to switch focus through the list of elements.
This is also why it's recommendable to set the neighbors up carefully.
So focus is making the control active without mouse control?