"Read Only" cells in VWD

Hello,

I created lots of rows for several tables in the "show table data" view of VWD 2008 recently.  I came back later, opened the same tables and found I couldn't update there. In some of the tables I get a message saying that the cells are read only. In others I don't even get the courtesy of that message.  But in all cases I can still update the table using SQL.  Does anybody know how or where to restore editing in the table data view?  Data entry is a lot quicker than SQL!

Thanks.

John
...