If you want to turn off this automatic expansion feature, you can do this by going to Tools > Options > Text Editor > C# > IntelliSense and unchecking Show completion list after a character is typed. Please note that this will turn off the IntelliSense auto-completion feature. If you only want to know where VS has a specific option to turn off the automatic expansion feature, it should be noted that VS does not currently have a separate module for this.