mainStack and subStack question???

[Ban Nguyen]

Hello,

On my application that I am working on, it has a mainStack and 5
substacks

On the mainStack (card 1), I put 5 buttons to go to subStacks

This is a problem:  when user clicks on button 1 to go to substack 1,
the substack 1 shows, but when user click on button 2 to go to
substack2, the substack 1 disappears.

Is there anyway to keep the substack 1 stays until the substack 2 shows
up?