Adjusting the curve to some Shapes makes it disappear??

[KittyKitKatx]

Hello I'm VERY new to Animator CC, this is literally my first day using it so I'm going through the tutorials that Adobe provides.

The 2nd Tutorial shows you how to make a 2d figure walking. He has you make a hill for the background using the pen tool. Then when finished you use your arrow and hover over the line of the hill. The arrow will show a curve feature letting you be able to adjust the shape and curve. I noticed I could fix some sides of the shape but when I adjust the left side of it, or the bottom of it the shape disappears completely.

Why is this happening? It didn't happen in the video and its not letting me be able to adjust the shape to my liking. Is this a bug? Am I doing something wrong?

[Colin Holgate]

Can you say which video? There are cases where overlapping curves can lead to whole areas disappearing. An easy solution to that sort of problem would be to draw different parts in different layers, or select some parts and group them together.

It's also possible to draw in 'Object Mode', where each area you make becomes its own object, and won't get harmed by the next set of curves you draw.