A method and system are provided for managing application programs with non-responsive user interfaces, possibly due to a bottleneck in handling eventsmessages. That system incorporates a three-position, four-way primary control valve which selectively connects a supply line and a tank return line to first and second hydraulic lines. 0:1, an average major axial diameter of 0. A first volume extends between the first and second apertures, and a second volume extends between the first and third apertures.