Splitting/merging table cells messes up table layout

[Lynne Kues]

Steps to reproduce

1. Create a table with 7 row, 5 cols. See attachment starting-table.png.
2. Merge right cell B3.
3. Merge right cell C4.
4. Split vertical cell B4.
5. Merge down cell E5. Then split vertical.
6. Split horizontal cell C4.

Expected result

Step 6 should split the cell horizontally and table layout should be maintained properly.

Actual result

The table layout gets messed up. See resulting-table.png.

[Jakub Ś]

Starting code:

<table border="1" cellpadding="1" cellspacing="1" style="width:500px">
	<tbody>
		<tr>
			<td>A1</td>
			<td>B1</td>
			<td>C1</td>
			<td>D1</td>
			<td>E1</td>
		</tr>
		<tr>
			<td>A2</td>
			<td>B2</td>
			<td>C2</td>
			<td>D2</td>
			<td>E2</td>
		</tr>
		<tr>
			<td>A3</td>
			<td>B3</td>
			<td>C3</td>
			<td>D3</td>
			<td>E3</td>
		</tr>
		<tr>
			<td>A4</td>
			<td>B4</td>
			<td>C4</td>
			<td>D4</td>
			<td>E4</td>
		</tr>
		<tr>
			<td>A5</td>
			<td>B5</td>
			<td>C5</td>
			<td>D5</td>
			<td>E5</td>
		</tr>
		<tr>
			<td>A6</td>
			<td>B6</td>
			<td>C6</td>
			<td>D6</td>
			<td>E6</td>
		</tr>
		<tr>
			<td>A7</td>
			<td>B7</td>
			<td>C7</td>
			<td>D7</td>
			<td>E7</td>
		</tr>
	</tbody>
</table>

After all these steps cell E4 gets rowspan 3 instead of 2 thus the error.

Problem can be reproduced even in CKEditor 3.x. It seems it has been always working that way.