Forms and Controls (Magic xpa 3.x)
Forms and controls are interactive to the user, and so are client-side expressions.
The issue here has to do with Control Properties. For instance, there are properties that control whether or not a control is visible, or if it is disabled, or that change the font or color of the control. When these properties are set using an expression, the expression is constantly being re-evaluated.
If a server-side expression were to be used in one of the properties, communication would have to happen every time the control was evaluated. Therefore, you cannot use server-side expressions in a control; you will get a syntax error.
Server-side expressions are marked with an 'S'.
In this section, you can find information about the following:
Using Server-Side Expressions
Other Issues with Controls