onPageShow, onPagePre, onPageLeave :: Page -> Action () -> Action ()
-- these names are special and bound by Show
onPageShow  p = event $ "Show" ++ showPageCtor p
onPageShow, onPagePre, onPageLeave :: Page -> Action () -> Action ()
onPageShow  p = event $ "Show" ++ showPageCtor p
onPageShow  p = event $ "Show" ++ showPageCtor p