After running a simple query in the SQL editor window, the data grid gets populated with data. The customer pulls up the the data grid divider (the horizontal pane that adjusts the window size) all the way up. He goes past the visible area of the active window (where the sql code is) up past the menu bar. The top section of the data grid does not stop at the top of the window. It keeps going so that the first rows in the data grid cannot be seen. Then there is no way to view the first rows of the data grid.
It looks like you can't unpin the data grid window when that happens. It appears to be managable in the beta because the pushpin never goes out of sight, unless you minimize the window some.
Waiting for fix in a future release of Toad for Oracle.