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bugs - Dynamic after Kernel restart/quit:


Bug introduced in V10.1 or earlier and persists through V11.2



[...] The behavior of Dynamics when the kernel quits has never been well defined or documented, although there does appear to be a difference between v9 and v10. [...] I have updated the bug report with your case [...]





After quitting the kernel only one Dynamic cell fires. And it does not matter how many are there.


Dynamic[DateString[], UpdateInterval -> 1]

Dynamic[DateString[], UpdateInterval -> 1]

Button["Quit", Quit[], Method -> "Queued"]

enter image description here


When one closes the notebook and reopens it, they work correctly.




  • Can I fix this?

  • Should I expect this?


Another example shows that custom GUI won't survive kernel quit:


DynamicModule[{init = False}
  ,
  Dynamic[If[! init, "init...", $SessionID]]
  ,
  UnsavedVariables :> {init},
  SynchronousInitialization -> False,

  Initialization :> (
    Pause[1];
    Echo[$SessionID];
    init = True
  )
]

(example from Tracking the progress of Initialization)


Echo confirms intialization fired after Quit[] but the view didn't change.


Win 7/10 V 10/11



p.s. Investigation with LinkSnooper reveals that calls to update DynamicObjects are still being made, just some objects don't care...




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