Problem with clearing and selecting rows in a hidden grid

For the Polymer Element version of vaadin-grid, we have found a problem with clearing selections and setting selections when the grid is hidden (display:none).  Our hidden grid is in multi-select mode.

I have attached the HTML file that I was using to show the problem, and a screenshot of the browser display.  Here are the steps to reproduce the problem:

• Click on a row in the Logical Name grid.  The corresponding row in the Role grid will be selected (checked).  Click on a few different rows to see how this works.
• Now, deselect the currently selected row in the Logical Name grid.  The corresponding row in the Role grid will also be unchecked.
• Click the “Hide Grid” button to hide the Role grid.
• Select a different row in the Logical Name grid.
• Click the “Show Grid” button to show the Role grid.  No rows are selected (no checked checkboxes).
• Now, in the Role grid, click on a checkbox for a different row.  You will now see 2 checked checkboxes – the one that you just checked and the “missing” one.
• Another option is to select all the rows in the Role grid, using the header checkbox.  Hide the grid.  Select a different row in the Logical Name grid.  Show the grid.  Most of the checkboxes are still checked.