AppLayout refreshing after navigation from child

I have problem with refreshing my App Layout. I have my class MainPanelLayout extending AppLayout with route “mainPage” and child route SubPanel wtih route

@Route(layout = MainPanelLayout.class,value = "mainPage/subPanel")

First when im logging then mainPage is opening after this im writing in address bar my link to SubPanel: localhost:8080/mainPage/subPanel and this action is firing constructor in MainPanelLayout again, whats more when i`m routing to address localhost:8080/mainPage then it is firing it again, after this refreshing is working fine(not firing constructor)
I have @PreserveOnRefresh annotation in both classes.

I want to run my AppLayout constructor only one time per browser tab, if i`m opening subroute i dont want to refresh my before created MainPanelLayout once more, becouse this is reseting my view to beginning.