What does this command mean?

[mr.dct]

I have another problem but about Qt Desinger. When I use the QGroupBox, it has no border like in that example. I tried to set "

border:1px solid rgb(x,x,x);

border:1px solid rgb(x,x,x);

To copy to clipboard, switch view to plain text mode 

" but it return a border with sqare edge, not curve edge like in the book. I though must use border-radius parameter but it didn't work too. Someone help me to set the right command, and make it the default style when creating a groupbox ??? Thanks.