A: 

Form.Opacity doesn't work for you?

Mladen Prajdic
I want it to completely disappeared. And I only want the boarders and not the whole thing.
Jonathan Shepherd
+1  A: 

That's just how the GroupBox control works. The Background property of that control includes the area that your screenshot points to. If you wanted to do a workaround for it, you should set the GroupBox background to be transparent as well, and draw a white box behind it, encompassing only the area you want to be white.

JoshJordan
I will see about that. Wait a sec.
Jonathan Shepherd
Good suggestion.
Nathan Taylor
Got it working, but your idea have a flaw in it. The name of the group box can't be seen after applying the idea. So I decided to remove the name altogether.
Jonathan Shepherd
Just put another white box behind the text you want to show.
JoshJordan
You can also "Shape" your form using the form's "Region" property. if you are looking to make a custom non-square shape this might be a solution. THis will also affect the controls on your form regardless of their transparencies.
DataDink
A: 

What is the GroupBox's parent container? Is it a Form or a Panel? Is that element also set to transparent? As a test I made a GroupBox and placed it on top of (inside) a Panel. I changed the background color of the Panel to red and the background color of the GroupBox to transparent and those ares of the GroupBox are properly transparent. My suggestion is to look at the parent container.

Also the GroupBox label may become hard to read in some cases, once the top strip is transparent.

JYelton
It's a normal form.
Jonathan Shepherd