You can set up the enabled flag of a text control at runtime based on the value of a checkbox control.
Procedure
Add a checkbox (Checkbox2) and a text control (Text Control2) into a vertical pane within the form.
Go to the General properties for the checkbox control.
Create a binding for the Value attribute of the checkbox and set it to the Enable property of the text control. The direction of this binding is from the check box Value to the Enable property of the text control.
When you load the form, the check box is in cleared condition and Text Control2 is in a disabled state. If you select the checkbox control, Text Control2 is enabled on the form.