In Oxygene, when you type the code, the CC shows the first in the list that starts with the characters that you typed.
In Microsoft C# and VB, the CC filters on the characters you typed.
Example in VB:
In the Microsoft solution, the list is getting shorter at each character you type, and in the list all that contains (instead of starts with) what you type is displayed.
This is very handy when you are searching for a type, by example a xxxxxxxxTypeReference.