OpenEuphoria

Unexplainable behavior

• Posted by Mike777 <anon4321 at gmail.??m> Jan 29, 2008
• 751 views

I'm posting this follow up under a new subject because I'm at my wits end on
this and would like somebody (anybody?) to take another look to see if anything
pops out.

I have a handler for a checkbox onClick event that I want to fire when the user
clicks on a label to the left of the checkbox.  I would presume this is fairly
common behaviour.

I programmed an invokeHandler command into the onClick event of the label and 
it certainly invokes the checkbox onClick handler when the label is clicked.

But there is a problem in that it appears to actually invoke the handler twice
when running at "full speed".  If it is slowed down by way of a sleep(1) command
or insertion of a message_box, either in the label's onClick or anywhere
downstream in the checkbox's onClick procedure it runs only once.

My label click procedure now looks like this:

procedure lblchkMyCheck_onClick (integer self, integer event, sequence params)
  atom myAtom
  setCheck(chkMyCheck,not(isChecked(chkMyCheck)))
  sleep( 1)
  myAtom = invokeHandler(chkMyCheck,w32HClick,{})
end procedure

My checkbox handler does a lot of things, one of which is to repaint virtually
every control on the screen (if that matters), along with present the results of
a calculation in a textbox (just one of many controls on the screen).

If I pull out the sleep(1) line, then the system does something that seems like
there is a bit of code somewhere I've forgotten about (which I generally refer to
as a poltergeist), because the above code runs twice, the first time with the
value of chkMyCheck appropriately changed from what it started out as and the
second time with the opposite.  That is, the second time it is run with the value
of chkMyCheck exactly as chkMyCheck started, thereby putting a result on the
screen which is the same as when I started (obviously a bit unproductive,
complete with the check mark appearing for an instant and then resetting itself
back to how it started.

If I insert any CPU halting mechanism at any point in time (a sleep command,
or a message box) then the second execution is not done, the check box is
appropriately changed only once and the value displayed in the textbox is the
correct (updated) value.

As another hint as to what is going on, if I remove the sleep and message box
commands, I can still get it to work, if I click on the label and hold down
the left click button for a full second before letting it up.  
 
I could understand how holding the left click button down might cause the event
to be registered twice, but this is the exact opposite.  By clicking quickly and
lightly it executes twice.  By clicking once (very slowly and heavily) it only
executes once.  Baffling to me.
 
If that is enough information to trigger somebody's (terrible) memory of
something similar I'd love to hear about it.

Thanks

Mike