C# textbox visibility question

Hi guys, I am relatively new at programming in C#. I have created a form which has a series of text boxes diplaying outputs from various places. This is all working fine, but I have an Options form which the user can select how many text boxes are showing and when they press OK this should reflect in the first form. This is where I get stuck. Using the code

form1.textbox1.visible = false;

Upon button click this does not reflect on the first form. If anyone could help, it would be much appreciated. If you need more code just ask.

Many Thanks