hi,
you can use standard visibility global variables to show\hide a control on page.
...
1.Define a globe variable "IsVisible" and set its "IncludeInDataSet" property be "yes".
2. Set the property visible of the control in the page be "IsVisible"
3. create a function SetVisible (var visible : Boolean) to set the value of the variable "IsVisible"
etc, etc,..
look at these posts: