On the student action drop down box
The credit selected students account option should be written in one colour, maybe blue
The debit selected students account option should be written in red
This is because they are next to each other and if you make a silly error like I did you can end up posting a credit instead of a debit to every student by accident then having to manually delete each one. If credits and debits throughout DSP were in a different colour it would be more obvious and clearer viewing.