title: Ext JS 4 - Editing only one row in a grid with multiple selected rows
body: <p>This is one of the requirements am working on. </p>
  
  <p>I have a grid with the selmodel as 'Ext.selection.CheckboxModel'. And to edit the grid rows, I can either use RowEditing or CellEditing plugins. So, here i what happens:</p>
  
  <ol>
  <li>I select multiple checkboxes/rows.</li>
  <li>Then I singleclick/doubeclick on one of the selected rows to edit the data in it.</li>
  <li>This deselects all the other rows except for the one I double clicked to edit.</li>
  </ol>
  
  <p>I don't want the other rows to be deselected. I should be able to singleclick/doubeclick on one of the selected rows and still keep the rest selected.</p>
  
  <p>When all are rows are selected.
  <img src="https://i.stack.imgur.com/zerX5.png" alt="enter image description here"></p>
  
  <p>After i double click on a single row, you can see the other rows getting de-selected.
  <img src="https://i.stack.imgur.com/9BPWa.png" alt="enter image description here"></p>