SNew error link

Hi.
I want to use the SColorGradientEditor.![9@I1M6]TQ7BV)DP}3B2@O@D.png|756x490](upload://kdrGvzeKMZG3hwUWL8ALFIeWNma.png)

Logs:
error LNK2001: “public: __cdecl FGradientStopMark::FGradientStopMark(void)” (??0FGradientStopMark@@QEAA@XZ,“public: __cdecl SColorGradientEditor::SColorGradientEditor(void)” (??0SColorGradientEditor@@QEAA@XZ)
public: virtual class FReply __cdecl SColorGradientEditor::OnMouseButtonDoubleClick(struct FGeometry const &,struct FPointerEvent const &)" (?OnMouseButtonDoubleClick@SColorGradientEditor@@UEAA?AVFReply@@AEBUFGeometry@@AEBUFPointerEvent@@@Z)
1>STCurveEditor.cpp.obj : error LNK2001: “public: virtual class FReply __cdecl SColorGradientEditor::OnMouseMove(struct FGeometry const &,struct FPointerEvent const &)” (?OnMouseMove@SColorGradientEditor@@UEAA?AVFReply@@AEBUFGeometry@@AEBUFPointerEvent@@@Z)
1>STCurveEditor.cpp.obj : error LNK2001: “public: virtual class FReply __cdecl SColorGradientEditor::OnMouseButtonUp(struct FGeometry const &,struct FPointerEvent const &)” (?OnMouseButtonUp@SColorGradientEditor@@UEAA?AVFReply@@AEBUFGeometry@@AEBUFPointerEvent@@@Z)
1>STCurveEditor.cpp.obj : error LNK2001: “public: virtual class FReply __cdecl SColorGradientEditor::OnKeyDown(struct FGeometry const &,struct FKeyEvent const &)” (?OnKeyDown@SColorGradientEditor@@UEAA?AVFReply@@AEBUFGeometry@@AEBUFKeyEvent@@@Z)
1>STCurveEditor.cpp.obj : error LNK2001: "public: virtual struct FVector2D __cdecl SColorGradientEditor::ComputeDesiredSize(float)const " (?ComputeDesiredSize@SColorGradientEditor@@UEBA?AUFVector2D@@M@Z)