To reproduce: use the following code snippet:


Steps to repeat:
1. A Self-Referencing Hierarchical Grid is displayed, grouped by the "Title" column.
3. Expand the first group.
4. Check the first row  check box. As a result the editor is activated and its value is changed.  
5. Click on the "+" sign in 1st row of data to expand and see child rows or just close the editor. You will notice that the group is unexpectedly collapsed.

Workaround:

private void radGridView1_ValueChanged(object sender, EventArgs e)
{
    if (this.radGridView1.ActiveEditor is RadCheckBoxEditor)
    {
        if (this.radGridView1.CurrentRow.Group != null && this.radGridView1.CurrentRow.Group.IsExpanded)
        {
            this.radGridView1.EndEdit();
            this.radGridView1.CurrentRow.Group.Expand();
        }
    }
}