i tested it again.
the error occurs if a blob field is not empty.

when i edit a line which contains an emtpy blob field all works fine.
But if there is data in the blob column, i always get an "changed by another user ... "-error.

i've tested it in a 2.project too. With only a grid,a dbnavigator ,an oraclesession and an oracledataset. I've created a table with 3 columns
2 varchar2 fields an a blob field. It has the same behavior.
If the blob field is filled i can't edit any field in the line.

furthermore i've seen ,that you can write data in the blob column (if empty) by writing in a blob-dbgrid-cell. you can see before "(HugeBlob)" and after "(HUGEBLOB)". Is this an error or a feature.
Because the user can't read his changing.