Commit_work on a form with multiple d.b. blocks

Question

Before I click on my "save" button, I manually insert some records into my detailed table 'AR_CASH_APPLIED'.
Then when the user clicks on "save", I go to each data block and commit_work.
Three questions:
1) Do I need to commit_work for each data block this way?
2) When does my previous "insert" statement actually get committed ?
3) Why does my CLEAR BLOCK command not clear all data from my screen. I still see data items for the AR_CHECK block.
Code is here (after the 'insert' has been issued):
     IF v_alert_response = Alert_Button1     THEN                    
     -- this is the cash batch entry block.                     go_block('ar_cash');
          commit work;                                   go_block('ar_check');
          commit work;                    
go_block('ar_invoice');
          commit work;                    
CLEAR_BLOCK;
go_block('ar_clients');                    
          ENTER_QUERY;
END IF;

Answer 1

Commit commits all outstanding transactions in all the blocks - there is no need to visit each one.
Likewise any DML that you've done in code through direct insert, update and delete statements will be committed by the commit_form or commit as well.
Issue an explicit go_block before you clear_block.