You need the user control to save its data, not sure what you need so can't give you any tips there yet. I don't know how they work, but you might be able to make them member variables on the form and never dispose of them.
My advice would be to set your area you want to display the user control in as a panel.
Upon clicking each menu item, you would have something like:
//This might be a member variable instead
DeSched Deschedule = new DeSched();