TPageControl's TDBGrid data not displayed

    I have a problem with the display of data when returning to a page in a
TPage Control. This application's main form includes a TTreeView control on
the left and a TPageControl on the right and they are tied together. The
page contains a DB grid which displays in three forms (one column, two
columns, or three) depending upon the selection made via a radio button.
    When I return from processing (initiated by the user via an Analyze
button on the toolbar), my DB grid data is no longer displayed. If I choose
one of the other tabs or one of the other nodes in the tree and then select
back to the desired page, the data is displayed. There are numerous other
pages/nodes that work fine, but the four with grids all behave as I
described above.

I would appreciate any help you can offer. Thanks in advance,