How to remove widget

UWidget::RemoveFromParent() called on
‘/Engine/Transient.UnrealEdEngine_0:Hive_game_instance_C_121.notyet_dialogue_widget_C_1.WidgetTree_0.keyword_panel_widget_C_1’
which has no UMG parent (if it was
added directly to a native Slate
widget via TakeWidget() then it must
be removed explicitly rather than via
RemoveFromParent())

This message shows up and i cant remove widgets using Remove from parent or Remove all widgets. Can anyone explain what this message implies?