In Sparta TabItem I have a webbrowser control and lets say I have a google search page in it... While am pressing the key V or Z its navigating to the tab Veritas or Zeus respectively with out pressing Alt Key. So I could not able to type in the google search
I think the reason is system can't tell which the proper key to handle is.
As you can see, I set the AccessKeyScope for each control to its own. So the shortcut key won't be triggered unless the control has focus.
Hope this may meet your requirement.
If you still have any concerns please feel free to let me know.