With your mouse point to the beginning of the line you want to copy click the left button and hold as your holding move the mouse so that the line you want to copy is highlighted. Once its highligted you can take your finger off the button but don't click on anything else. Then on the keyboard hold down the control button and the c button this will copy the line. Then go to your profile on SB and click on the signature box when you see the cursor click on the control button and the v button together and this will copy.