fix customtreectrl style for mac
fix customtreectrl style for mac

SasView/sasview,lewisodriscoll/sasview,lewisodriscoll/sasview,lewisodriscoll/sasview,SasView/sasview,SasView/sasview,SasView/sasview,lewisodriscoll/sasview,SasView/sasview,SasView/sasview,lewisodriscoll/sasview