Showing or hiding a control
You can show or hide a UI control object based on a predefined condition by editing attributes of its corresponding control element in the controls.xml file.
About this task
When a control is shown, it is created at run time and occupies space on the screen. When a control is hidden, it is not created and occupies no space. A shown control may not be visible, based on its state and the conditions specified in its <invisible> and <visible> attributes in the controls.xml file. You can use this functionality to customize the availability of a control based on conditions you specify. For example, you may want to show a given control when a user selects one type of content (such as a data module), but hide it when other types of content are selected. To do so, add the applicable conditions to <shown> and <hidden> tags within the control's definition in the controls.xml file.