If you set your posting control(s) to use control type C58 mandatory pre posting, the pre posting box will pop up upon saving, automatically..  For example if I set up posting control M109  Pre Accounting Material Requisition Header, for Code Part Name: Account, Control Type: C58  Mandatory Pre Posting and then enter a new Material Requisition Header.  Upon saving the Material Requisition Header, the Pre Posting pop box will automatically appear.  Please see if this will help you resolve your issue. 

Thank you! Yes, it is easier to use ESC the few times we don’t want the preposting than use the mouse every time. :)