Unfortunately the setup of the child splitter is not correct for the described scenario. To have the child splitter hidden during init along with the parent splitter, please, make sure the ResizeWithParentPane is true. Otherwise the child splitter does not take into account it is within a splitter. Since it is initialized before the parent splitter, the child is shown right after initialize, without checking for any parent, since it does not know it should. Hence the behavior described by this item.