What exactly do you mean by "square portion of the object"? I don't fully understand what's happening to you yet (sorry). I assume you are trying to make curves based on a reference image you have in your viewport, correct? And in the view port you can see the outline of the house (the curve you made) until you click on the outline?

Trying to figure out if you have a camera placement issue, or maybe camera far clipping issue. Or even image placement issue. Or like what was already mentioned...the curve color being the same color as the grid.