Whenever I use a rectangle tool to fill up any shape its not working as it should be. Instead of filling up the shape it snaps and then makes a line across two corners of my shape.
Also, I use sketch up 2015 pro due to the fact that I use sketch up for educational purposes as my school sets us homework or more of a finish-at-home type of work
How about uploading a SketchUp file that demonstrates this problem. I expect the Rectangle tool is working correctly even if it doesn’t do what you expect.