How to get Rect of Popup menu in mfc(with C++)?

问题

I developed button and popup menu like this.

I want to process like this.

1. When the mouse pointer is hovering Button A, show Popup Menu(1) and (2).

1-1) When the mouse pointer is hovering Popup Menu (1) or (2), show the popup menu continuous.

2. When the mouse pointer is leaving from Button A to Popup Menu Area(in case - hovering B or C), close the popup menu.

So I've wondered how to get Rect Area of Popup Menu and how to know mouse pointer hovering the Popup menu.

Please send me some answer TT.. Thanks.

来源：https://stackoverflow.com/questions/59389778/how-to-get-rect-of-popup-menu-in-mfcwith-c