Software configuration - VA 10.5.1724.0, Visual Studio .NET 2003 and Windows Vista Home Premium
Even if the "Any character not valid in a symbol" checkbox is unchecked (under Options->Advanced->Listboxes->Selections commited with...), the highlighted suggestion is inserted in the code when I press ';' (or any character not valid in a symbol).
"Selections committed with" behavior for member lists is now configurable under VA Options | Advanced | Listboxes. (case=9369), implemented in build 1829.