That's why you never want to modify the default policies.
Duplicate them, modify the duplicate, and assign the duplicate policy in the ACL entry.
The buttons at the upper right determine what happens when you save a resource. I can't remember what the official names are, but the options are close, continue editing, and add another.
"Continue editing" (the default) leaves you with the same object on the screen when you save. The "add another" is for when you want to create a bunch of objects in a row -- when you save one, you get a new blank form for entering the next one, but you have to remember to turn that off when you're done.
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PLEASE, PLEASE specify the version of MODX you are using.
MODX info for everyone:
http://bobsguides.com/modx.html