Several times I have imported a jpg of a floor plan, then started outlining the walls with the line tool. Then using the rectangle tool I start filling in the elements, such as a future coffered ceiling. Then, magically, the rectangle tool stops working. My guess is that it is no longer on the same plane as everything I have drawn. Perhaps one line goes up or down, and the rectangle tool stops working because there’s a twist or something.
What is an easy way to fix it? What is a way to force all of what you draw, before pulling it into 3D, onto one flat plane?