Every Tools that can contain Tools by itself, like the DECISION (IF and ELSE), Duplicate, Loop, LoopNode, Switch (CASE and ELSE) have one PreEvent and one PostEvent node. The same counts for Product, SubProduct and Supplier and Functions and Validations. Pre- and PostEvent are always there, but not necessarily shown. Showing a Pre- or PostEvent can be done from the contextmenu of the parentnode, using Show PreEvent or Show PostEvent. If Pre- or PostEvent nodes contain childnodes, they are always shown by default.
PreEvent
You can place Tools below a PreEvent. The PreEvent itself has no Pre- and PostEvent. The Tools below a PreEvent are always executed before the Tools of the ParentNode are executed. So the PreEvrent can be used for initialization purposes.
PostEvent
You can place Tools below a PostEvent. The PostEvent itself has no Pre- and PostEvent. The Tools below a PostEvent are always executed after the Tools of the ParentNode are executed. So the PostEvrent can be used for finalization purposes (like calculating totals, etc.).
