how do i change another interface like venturing in other forms, without going through hiding lots of the panels?. thanks!

Make the 'layer' value of the object/form a higher number than all the other panels?
Question isnt too clear.

i mean, it's like in the main menu of the game,. there are buttons like play game and exit,. then if i click the play game button, i like to change the interface without hiding the previous panel,. just want to show the next menu,.

Have/create another panel whose 'layer' value is higher than the 'main' menus value.
Then set the new 'sub-menu' visible and if its layer value is higher than the main menu
it will appear on top of the main menu.

Is that what you mean?

Replacing the contents of the main menu with new buttons/options etc is WAYY too much hassle.

so in that case it will only just overlap?

Thats right. Any bits of 'main menu' that are sticking out around the edge
of your new menu will still be visible (and clickable).

Also, any bits of your new panel that are translucent (using alpha transparency
or OVERLAY flag) will still show the 'main menu' behind it, but the old
'main menu' bits that are visible "through" this panel are not clickable.