split merged cell vertically command transposes the cells

[Zoltan Koszegi]

Description (I attached a detailed image that shows every aspect of this issue well - please see it):
1) Create a cell and fill them with numbers - just for knowing where the cells moves at the end.
2) Merge down a cell at the right edge of the cell.
3) Split the merged cell vertically.

RESULT: The new cell comes to the first place of the affected row instead of the place where the split command was applied. Every other cells are shifted right. Note: If the merge/split action is applied to an intermediate cell (not on the last one in the row), there is no issue.

I can recreate it with the demo page with IE9, IE10.

[Jakub Ś]

Problem can be reproduced in every browser from CKEditor 3.1.