mouseDown message sent but not triggering the handler in a behavior

[Andre.Bisseret]

Bonjour,

On a stack, in a group, I have a button which is supposed to show a  
field on mouseDown and hide this same field on mouseUp.

The two handlers (mouseDown and mouseUp) are in the script of a  
behavior button to which the group is set.

When opening the stack, on a first mouseDown on the button, nothing  
happens (the field is not shown).

However, the message watcher shows that, after a mouseEnter message, a  
mouseDown message is actually sent!

Now, the field is shown as expected only on a second mouseDown! and  
then all keeps been as expected: any subsequent mouseDown triggers the  
visible of the field! (if I close the stack and reopen it, the same  
phenomena is repeated).

I have another button on the same card, with a similar handler  
(showing a field on mouseDown and hide it on mouseUp) which works  
normally. The difference is that for this one, the handler is directly  
in the script of the button.

Am I missing something about messages/handlers in behavior buttons?

Any help would be much appreciated

Best regards from Grenoble

André