The RadContextMenu allows you to specify a delay for the closing and opening actions of its child items. This means that you make the RadContextMenu wait for a specific amount of time before opening or closing a sub menu. In order to specify these delays you can set the ShowDelay and HideDelay properties. They are of type Duration and have the following format in XAML "0:0:0.00".
Here is an example of a RadContextMenu with a delay before opening a sub menu equal to one second and a delay before closing a sub menu also equal to one second.
<telerik:RadMenu VerticalAlignment="Top" ShowDelay="0:0:1" HideDelay="0:0:1"> ... </telerik:RadMenu>