It is not fully clear to me what you are looking for, so I will make the following assumptions:
* The text of the menus should still be horizontal.
* The Menu Header should be on the left side of the window.
* You want the sub menus to work like current pop-up menus currently do.
I would put this into it's own OCX, so that you can reuse it.
Create an OCX project...
There will be two custom controls in this project. One that is each root menu item, and one that will be the menu header (on left side of window).
The idea here is that a standard pop-up menues aready work the way you want the sub menus to work. So all we need to do is create a menu header on the left side of the screen to act like the menu header at the top of the screen does.
The first thin we should do is get the graphic for the arrow pointing right. I would get/create the same one that you see when you use the standard menus for consistency.
Now create a new control with a label and a picture box. Use the UserControl_Resize to allign the picture of the arrow with the text.
Add a popup menu to the control, and add properties/functions to all the customization of the menu items at runtime. When the user clicks on this custom control, you should have it display the popup window. You may want to investigate how to have the popup align with the top & right of your control, so that it looks more like its directly connected to it.
Now create a new control that has one of you root menu items on it. (Make this a collection array). You will be adding more of these at run time.
Have this control display one of the other controls that you created for each root menu items (at runtime). It should manage the spacing between the controls, and the width of the controls for consistency.
John R Lick