It's observed that if we have a programmatically-selected row in a data table then a subsequent click on any other row of the table doesn't deselect the programmatically selected row (this happens in both the modes - single-select and multi-select).

Note: This issue is specific to EE jars. For the community jars this problem is observed only in single-select mode and seems to be fixed for multi-select mode (also have a look at this related link - http://www.icefaces.org/JForum/posts/list/12123.page)

Attached with this case is a sample that exhibits the issue.
Scenario 1:
1. Select a row by clicking on it.
2. Click "Move Up" button to move the select row one level up.
3. Now click on another row
4. Observation - The clicked row gets selected but the row which was moved also remains selected.

Scenario 2:
1. Click "Add" button to move add a new row that's pre-selected / programmatically selected.
2. Now select another row
3. Observation - The clicked row gets selected but the row which was added also remains selected.