Master/detail relationship doesn't show records

I have three table related together with master detail relationship like
this

table1 master of table2
table2 master of table 3

I'm using a lookupcombobox to filter the second table showing on a
dbgrid1.
The third table is shown in a second dbgrid2 bellow the seconds in the
table.

My problem is that when I'm moving through the grid1 the records of the
dbgrid2 shows up only for the first record the second one seems empty
but when i try to insert a record two times i get a key violation
message through the bde.Opening the table through the database desktop
the records are in there nothink is missing but my application doesn't
show them at all.

Please any ideas it's ergend.

I must delever a beta version tomorow and I'm stack with it.

Regards

Johnny