If the spreadsheet data entry area is frozen, appears grayed out, and you can't enter data, you most likely have a layout that didn't restore properly.  It is easy to fix:  Reset the layout by clicking the far left icon on the sub-toolbar just above the data area and then select the RESET (or Reset Layout) menu option.

If this doesn't resolve your issue, try the following:

1. Click Help...About Logbook Pro
2. Double-click the scrolling image in the center of the dialog
3. Near the bottom you will see an option to Purge Layouts, click this option
4. Close and Restart Logbook Pro