if (getRversion() >= '2.15.1') globalVariables(c('buttonsFrame', 
 'dcFrame', 'dcVariable', 'distFrame', 'distVariable', 'formulaFrame',
 'methodtypeFrame', 'methodtypeVariable', 'outerOperatorsFrame', 
 'rhsVariable', 'subsetFrame', 'subsetVariable', 'top', 'xBox',
 'yesVariable', 'designmethodVariable', 'designmethodFrame'))