[FF] createBookmark problem with multi-ranges

[Garry Yao]

If a selection contains multiple ranges, now invoke selection.createBookmarks(), if the ranges were overlapped with each other, then the bookmarked range will right correct.
Try the following selection in FF:

<table>
    <tbody>
        [
        <tr>
            <td>
                cell1
            </td>
            <td>
                cell2
            </td>
        </tr>]
    </tbody>
</table>

FF will translate it into multi-ranges as:

<table>	
    <tbody>
        <tr>
            ^<td>
                cell1
            </td>^
            ^<td>
                cell2
            </td>^
        </tr>
    </tbody>
</table>

Now the bookmark nodes creation on every range will interfere with each other, resulting in incorrect bookmark positions.

[Garry Yao]

Since other browser doesn't support multi-ranges, this should be FF only.

[Garry Yao]

See #3475 as a concrete bug of this.

[Frederico Caldeira Knabben]

So here again, it looks like it's enough to loop through the ranges from last to first, instead of first to last, when creating the bookmarks. Just my intuition though.

[Garry Yao]

See #3475 for a practical way to avoid this problem.