Why does 'delete stack' sometimes not work?

[Mike Bonner]

Silly question but.. If the mainstack has a bunch of substacks, and you try
to close and remove the mainstack from memory while the substacks remain
open, is this even possible?  Substacks have a mainstack property, and it
seems the message path is kinda hardwired in that instance.  If you do
manage to close and delete the mainstack all its substacks should go away
too (but the error appears instead)

I tried an experiment.. I made a mainstack and a substack.  Just because, I
turned the substack into a palette. trying to delete the mainstack while
its still open gives me the error you refer to. Closing the mainstack of
course works fine. (and yes, the cantdelete of the mainstack is set to
false)  Then deleting the mainstack after its closed (from the message box)
effectively kills the mainstack, AND the substack and (in version 9) pops
up an empty error dialog.
Placing a button on the substack that attempts the deletion of the
mainstack (first closing, then deleting) fails and causes the error you
note.

You said it works with a stack with 1 palette substack.. The palette
substack.. does it actually have the mainstack set AS its mainstack?

On Wed, Oct 19, 2016 at 9:37 AM, Graham Samuel <livfoss at mac.com> wrote:

> I am still going on about how to reliably execute ‘close stack and delete
> from memory’ via script. I’m using LC8.1.1 rc2 on a Mac. The latest pickle
> I’ve got into is this:
>
> I have a stack “myMainStack”, which has quite a few substacks - they’re
> palettes which user can open to access tools etc. All of them have their
> ‘cantDelete’ property set to false. I have a menu which includes an item
> for resetting the program, which involves deleting the stack “myMainStack”
> both in RAM and on disk, and then reloading it from a file in the program’s
> resources folder. In the IDE, I invoke this menu item and step through
> until it executes:
>
>  close stack “myMainStack”
>
> Then the actual mainstack’s window closes. Those palettes which were open
> stay open. I have a feeling that the whole thing should close (this is an
> option I chose for the mainstack - ‘purge stack on close’, ‘purge window on
> close'), but never mind, that’s what happens.
>
> If I then execute
>
>  delete stack “myMainStack”
>
> from the message box, I get
>
> > Message execution error:
> >
> > Error description: Object: stack locked, or object's script is executing
> >
> > Hint: button "File" of group “mytMenu" of card “MainDisplay" of stack
> "/Users/Graham/Library/Application Support/PointPlots/
> myMainStack.livecode"
> >
> >
> As the stack is closed, it can’t be executing scripts: it’s not locked in
> that its ‘cantDelete’ property is set to false. Furthermore the file
> mentioned in the error message isn’t there, because my program deliberately
> deleted it earlier in the script. So this error makes no sense, but why
> should it be an error at all? The engine ought to be pointing at the stack
> in RAM, not on disk - the Project Browser says it’s there still.
>
> Trying to test this with a simple mainstack with one palette substack does
> not exhibit the problem.
>
> This apparently simple requirement is driving me crazy.
>
> TIA for any help.
>
> Graham
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