Hi,
extension does not work when you have more than one window for single VS instance.
For example when you grab and move some tab into separate window and you move that window to the second monitor, then mouse navigation works only in the window you have currently focused, then it does not matter when you move the focus to an another window as the sequence chain seems broken with the change of focus.
The keyboard (ctrl+- and ctrl+shift+-) shortcuts works just fine in those cases.
BR,
M.