Percentage promotions improperly applied

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Create a % based promotion 
2. Add an expensive item to your cart
3. Check out and apply promotion
4. Add an inexpensive item to your cart
...Notice the % for promotion with expensive item only applies
5. Remove expensive item
...Notice the % for promotion of expensive item applies still

What is the expected output? What do you see instead?

Promotion is not being re-checked when items are added or removed from cart. 
Allows many bad things to happen.

Please use labels and text to provide additional information.

Original issue reported on code.google.com by subim...@gmail.com on 16 Sep 2010 at 5:40