Conditional show/hide of buttons and table controllers?

Question

I'm using the following code in my groovy script to hide or show a button and a table controller in the form. But this is not working and not making any difference in the show/hide of the screen elements. This script is called on a button click in SAP advanced workflow form.

form.getButton(<button_name>).hide()
form.getWidget(<table_controller_name>).hide() 

and

form.getButton(<button_name>).show()
form.getWidget(<table_controller_name>).show() 

If someone can hep me in finding where I'm missing something then it will be greatly appreciated.