preopenstack handler interrupt?

[Ron]

Greetings,

I have a mainstack with a preopenstack and openstack handler in the  
card. In the preopenstack handler there is a call to write out a  
preference stack from a custom property, then open that stack, read  
data from that stack and then continue with other operations.

My question is, is the preopenstack handler of the main stack  
completed before any preopenstack handlers in the preference stack? or  
does the call to open the preference stack interrupt the main stacks  
preopenstack handler?

Thanks if you can follow this...

Ron