Indent command on multiple table cells incorrect

[Garry Yao]

Environment

Firefox

Reproducing Procedures

1. Open any sample page, load editor with the following content and selection (multiple cells selected):

   <table>
   	<tr>
   		<th>[head1]</th>
   		<th>[head2]</th>
   	</tr>
   	<tr>
   		<td>[cell1]</td>
   		<td>[cell2]</td>
   	</tr>
   </table>
   

2. Click on 'Indent' command;

• Actual Result: Only the first cell (head1) get indented.
• Expected Result: All cells get indented.

[Jakub Ś]

It seems it is still an issue in CKEditor 4.x and Firefox.

When I select all cells with mouse only first one gets indented.

This issue is related to #3140 which concerns indenting whole table.