The Open File in Solution dialog and the List Methods in File drop-down consider recently accessed items to determine a selection when filtering. The policy lets one visit successive items easily.
Set the registry if you prefer that Visual Assist always pre-select the first alphabetical match of a filtered list.
Visual Assist build 2097 and newer
Change:
HKCU\Software\Whole Tomato\Visual Assist X\<IDE spec>\SelectRecentItemsInNavigationDialogs = 00
Set the value to 01 to restore default behavior.
Visual Assist build 2094 and older
Create the following STRING value:
HKCU\Software\Whole Tomato\Visual Assist X\SelectRecentItemsInNavigationDialogs = "No"
Delete the entry to restore default behavior.