fix SortableContainer as props filter

[chinesedfan]

Lots of users are confused about the usage of SortableContainer. (#67, #68, #69, #71)

I am not sure whether this is the best way to fix. But at least it works for me. :)

[coveralls]

Coverage decreased (-0.03%) to 95.265% when pulling b7acc53 on chinesedfan:feature/1008_fixContainer into 4d7dbe6 on jasonslyvia:master.

[coveralls]

Coverage decreased (-0.03%) to 95.265% when pulling f33613b on chinesedfan:feature/1008_fixContainer into 4d7dbe6 on jasonslyvia:master.