I think he's telling you about fire just 1 time, if you fill this.tag the next activate will not work.
You need to create a funtion or procedure called from each page when it's being activated.
So in activate of each page you put by example: thisform.pageactivated(this.pageorder)

>>Hi everybody,
>>
>>I have a pageframe class and I don't have a page class. What would be the easiest way to fire some code when the individual page is activated (in particular, I'd like to change its font properties)?
>>
>>Thanks in advance.
>
>Usually, I do it from Activate event
>
>If Empty(This.tag)
> This.Tag='A'
> This.Setall(...)
>Endif
>
I'm not sure I get the idea