static JSplitPane jvsplit(Component etc n, Component etc s) {
  ret jvsplit(n, s, 0.5);
}

static JSplitPane jvsplit(Component etc n, Component etc s, double splitPoint, int delay default 0) {
  ret setSplitPaneOnFirstShowing(
    swing(-> new JSplitPane(JSplitPane.VERTICAL_SPLIT, wrap(n), wrap(s))),
    splitPoint, delay);
}

static JSplitPane jvsplit(double splitPoint, int delay default 0, Component etc n, Component etc s) {
  ret jvsplit(n, s, splitPoint, delay);
}

Began life as a copy of #1005756