By default, suggestion lists of Visual Assist remain open as long as there are longer entries to suggest.
Consider the three symbols:
int nTotal, nTotalHeight, nTotalWidth;
If you type nTotal, you will see three suggestions: nTotal, nTotalHeight and nTotalWidth, even though nTotal matches exactly what you typed. If you want suggestion lists to close immediately upon typing of a valid symbol, set the following registry key:
HKCU\Software\Whole Tomato\Visual Assist X\<IDE spec>\CloseSuggestionListOnExactMatch = 01
Set to 00 for the default behavior. Close all instances of the IDE before editing the registry to ensure your changes are not overwritten at IDE exit.
It also applies to include suggestions - if you type "string" and there is an exact match without an extension, the listbox will close at that point.