While deleting a few (400!) records from a master table (in a development database), I realised that PgAdmin just wouldn't stop displaying 400 error messages informing that each of the deletes failed (in this case because a foreign key dependency would not allow the delete to succeed).
I think a good solution to this would be that after the initial confirmation for deletion in EditGrid, the first error (during delete process) should allow the user to cancel further deletes. This can help a great deal, for e.g. in cases when the user realises his mistake as soon as the first error pops up.
Attached is a patch to do the same. Note, that the 'reconfirmation' is done only on the first error. So this takes care of another possible case when the users 'knows' that some random 20 out of his 500 deletes would fail !
