As described in your other forum post here
we have created a sample project. In it we have extracted the RadMenu and RadMenuItem implicit styles from Telerik.Windows.Controls.Navigation in Themes.Implicit folder in your RadControls installation folder as shown in this
If we understood you correctly you want to change the overlap between the submenu`s popup and the same submenu. To do this you can change the popup HorizontalOffset in the RadMenu and RadMenuItem implicit style (default set value is -1). We have done this in the attached project in the MenuImplicitStyles.xaml file:
<!-- NOTE: changed from HorizontalOffset="-1"-->
You can check the attached screenshot where the offset is marked with red.
If this is not the behaviour you wanted and you have anything else in mind, please send us a screenshot what you expect (with overlapped popups) and if possible a sample project to reproduce the issue.
You can contact us in case of any concerns and problems!
the Telerik team