Issue Description:

I will use example to describe the problem I face and how it should be.There are 4 sections in the collectionView and each section has different item size. Now, I give the height of itemSize for

0th section = 100
1st section = 0
2nd section = 150
3rd section = 200

The drawing on the phone only show the 0th section. But I expected that the drawing should show 0th, 2nd and 3rd section. Because I only set the height of 1st section = 0