Well, puzzle carefully over what an ActiveLayoutObject really is.
The activeLayoutObject is the one that the cursor is in. This can included a button; if the button is in the tab order.
Hiding stuff is odd sometimes.
I have sometimes used a global variable. Set the variable to "1" on panel switch and "0" when you leave.
I also sometimes use a Case() because FM has trouble with the straight bool expression or value in the hide section. This generally always works.
Case ( $$variable =1; 1; 0)
Case ( Get(ActiveLayoutObjectName) ="swashbuckler"; 1; 0)
The attribute is called "isFrontTabPanel".
It works, only thing is you need to refresh either the layout or the button object.
You can trigger the refresh via the slide control triggers.
I figured out what I needed to do to get the result I wanted....
1) Move problem button off of the popover.
2) Select the panel on which I want a button to appear.
3) Go to Insert/Button.
Bingo. The button only appears on the first Panel. No "Hide object when" necessary.
You're correct, since version 14 it is, but isFrontTabPanel works in 14 as well.
I guess they kept it for legacy reasons.