reconnectOn: aSession
    "find a right element and a context (at start we have only their ids)"
    "deal specially with page unload event"
    | object app |
    object := aSession site urlResolver ooRefFromURL: self relativeUrl.
    app := aSession webAppFor: object.
    app isNil ifTrue: [^self].
    self context: (self context notNil
        ifTrue: [app contexts at: self context]
        ifFalse: [app contextForView: self pageView]). "for unload event"
    self context isNil ifTrue: [^self].
    self context event: self.
    #unload = self event ifTrue:
        [app contexts
            detect: [:ctx | ctx window id = self element
                ifTrue: [self element: ctx window. ^self] ifFalse: [false] ]
            ifNone: [self element: nil. ^self] ].
    (  #( #load #newtab) includes: self event) "page events"
        ifTrue: [self element: self context page]Cascading not expected ->;  "element is entire page"
        ifFalse: [self element: (self context elementId: self element)].