Make child MenuItems appear to the right when selecting MenuItems

I am creating a menu using WPF. Every Menu Item has multiple child MenuItems that can also be selected. My problem is that when a Menu Item is selected the child menu Item appears to the left of the selection. I want the child MenuItems to appear on the right, but I cannot figure out how to modify this behavior. Thanks in advance!

Here is a diagram of what is happening:

                              ChildItem1  <-   MenuItemSelected

                              ChildItem2

Here is what I want to happen:

                              MenuItemSelected -> ChildItem1

                                                                 ChildItem2