NdefPresetGui "sto" and "del" buttons seem to be broken ?

NdefPresetGui "sto" and "del" buttons seem to be broken ? on SuperCollider 3.13.0.

both throwing:

ERROR: Message 'flipY' not understood.
Perhaps you misspelled 'copy', or meant to call 'flipY' on another receiver?
RECEIVER:
Instance of Point {    (0x55a11d12a8, gc=F0, fmt=00, flg=00, set=02)
  instance variables [2]
    x : Float 116.000000   00000000 405D0000
    y : Float 30.000000   00000000 403E0000
}
ARGS:
CALL STACK:
    DoesNotUnderstandError:reportError
        arg this = <instance of DoesNotUnderstandError>
    Nil:handleError
        arg this = nil
        arg error = <instance of DoesNotUnderstandError>
    Thread:handleError
        arg this = <instance of Thread>
        arg error = <instance of DoesNotUnderstandError>
    Object:throw
        arg this = <instance of DoesNotUnderstandError>
    Object:doesNotUnderstand
        arg this = <instance of Point>
        arg selector = 'flipY'
        arg args = [*0]
    < FunctionDef in Method ProxyPresetGui:makeViews >
        arg but = <instance of Button>
    Button:doAction
        arg this = <instance of Button>
        arg modifiers = 0
    Button:prDoAction
        arg this = <instance of Button>
        arg mods = 0
^^ ERROR: Message 'flipY' not understood.
Perhaps you misspelled 'copy', or meant to call 'flipY' on another receiver?
RECEIVER: Point( 116.0, 30.0 )

tested with:

(
~presets;
s.waitForBoot({
    {
        Ndef(\x,{\test.kr(1)}).play;
        Ndef(\x).addSpec(\test, ControlSpec( 0, 1000) );

        1.wait;
        ~presets = NdefPreset(Ndef(\x));
        { NdefPresetGui(~presets, Ndef(\x).controlKeys.size+1); }.defer;
    }.fork;
});
)

~presets.addSet(\boing); // works

supercollider-quarks / JITLibExtensions

NdefPresetGui "sto" and "del" buttons seem to be broken ? #34