Clicking sort button several times leads to different results in Chrome.

[lvganfei]

When test "../test/demo/test-grid-tree.html" page. After adding new row and clicking sort name or id column, the grid return different sorting result upon each sorting.
Steps to reproduce:

1. Open "../test/demo/test-grid-tree.html" page in Chrome.
2. Click the "add row" button.
3. Click the "sort id" button, observe the sorting result.
4. Click the "sort id" button again, observe the sorting result.
5. Click the "sort id" button several time, compare each reuslt.
   6 Click the sort icon in the id column header.

Actual result:

1. the sort result changes each time the "sort id" button clicked.
2. the sort results are not same as the one which click the sort icon.
3. The sort icon in column header doesn't change during Step 3 - Step 5.