Why My UMG widget reference '/Script/UMGEditor' asset?

I try to use UMG under windows platform. But when I cook assets for windows and run simple app to load UMG asset under windows, I receive the error ‘Package contains EditorOnly data which is not supported by the current build or vice versa’ always. I checked the asset reference by ‘reference viewer’ on editor and found my UMG widget referencing '/Script/UMGEditor’asset. Why? How can I delete this reference?

[2015.11.16-14.19.58:356][ 0]LogLinker:Warning: Unable to load package (…/…/…/…/UnrealEngine-4.10.0/…/Unreal Projects/MyUMGLab/Content/WMyUserWidget.uasset). Package contains EditorOnly data which is not supported by the current build.
[2015.11.16-14.19.58:356][ 0]LogLinker:Warning: Unable to load package (…/…/…/…/UnrealEngine-4.10.0/…/Unreal Projects/MyUMGLab/Content/WMyUserWidget.uasset). Package contains EditorOnly data which is not supported by the current build.
[2015.11.16-14.19.58:356][ 0]LogUObjectGlobals:Warning: Failed to find object ‘MyUserWidget /Game/WMyUserWidget.WMyUserWidget’