To reproduce:
Select a table in the object browser window.
Select Grant Wizard from the Tools menu.
or
Right click on a table in the object browser and select Grant Wizard.
Note the Selection window does not list any tables, and OK cannot be
selected after adding the permission information. It appears the
Selection window should have an entry for the table that was current in
the object browser window.
I just checked and the same problem appears in 1.6.3. If the Grant Wizard
is not supposed to work for a single table, perhaps those menu options
could be disabled.
(Or maybe I'm just missing how it's supposed to work?)