What can I do if I don't want to uncollapse a thread after i read it

[Dan]

Hi folks,

In my muttrc, i included the line:

        folder-hook . 'push <collapse-all>'

So every time i get into mutt all threads would be collapsed.

but after i read a new message and returned to index, the thread contains that 
message would be uncollapsed. what should i do if i want to all threads stay 
collapsed even after i read messages?

Best,

Dan