By default, when using Move Implementation to Source File or Create Implementation on a class to move or create several implementations in one go, Visual Assist places one blank line between each implementation.
Set the number of blank lines in the Visual Assist options dialog.
Visual Assist build 2059
You can set the number of blank lines by editing the registry value:
HKCU\Software\Whole Tomato\Visual Assist X\<IDE spec>\LinesBetweenMethods
Set the value to 1 to restore default behavior.