How can I setup my menu strip to act in the following ways (VB.NET)

Depending on the value of a boolean variable, I want the menu item to act in the following ways:

If the value is false, I want the menu to act like it would normally.

If the value is true, I want to force the user to have to click on the main menu to display the menu list. I do not want the user to be able to hover their mouse over a main menu to see sub menu, even if a sub menu list is already displayed.

Here is the background reason why :

File <=== Main Menu
- Open <==== Sub menu
- Save <==== Sub menu
...

Here's the background information and reason why I need it to act this way

One of my menus have a very long list of sub menus. The user has to go through these lists from top to bottom in order. All sub menus open up a form. For example, I'll say the beginning of the menus is "A" and the last menu option is "Z".

When the user clicks on sub menu "A", a form appears.
When they close the form, the menu option they most recently clicked on is displayed with the most recent sub menu a different background color. This works great.

My problem is caused by three things:

1. my MDI style application has the minimized, restore, close buttons are located at the top left (not top right as normal).

2. My menu strip is on the top and is horizontal (left to right). The menu lasts two rows so when the user closes a form, they can't move anywhere without hovering the mouse over a different main menu.

3. When the user closes the form, the sub menu is displayed properly but when the user moves the mouse over a different main menu, that sub menu is displayed (making the most recently clicked on one disappear). I'm trying to prevent this.