Index: ps/trunk/source/tools/atlas/AtlasObject/AtlasObject.h
===================================================================
--- ps/trunk/source/tools/atlas/AtlasObject/AtlasObject.h
+++ ps/trunk/source/tools/atlas/AtlasObject/AtlasObject.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2019 Wildfire Games.
+/* Copyright (C) 2021 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -166,6 +166,7 @@
 	void add(const char* key, AtObj& data);
 	void set(const char* key, const char* value);
 	void set(const char* key, AtObj& data);
+	void unset(const char* key);
 	void setBool(const char* key, bool value);
 	void setDouble(const char* key, double value);
 	void setInt(const char* key, int value);
Index: ps/trunk/source/tools/atlas/AtlasObject/AtlasObjectImpl.h
===================================================================
--- ps/trunk/source/tools/atlas/AtlasObject/AtlasObjectImpl.h
+++ ps/trunk/source/tools/atlas/AtlasObject/AtlasObjectImpl.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2019 Wildfire Games.
+/* Copyright (C) 2021 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -48,6 +48,7 @@
 	const AtNode::Ptr setValue(const char* value) const;
 	const AtNode::Ptr addChild(const char* key, const AtNode::Ptr &data) const;
 	const AtNode::Ptr setChild(const char* key, const AtNode::Ptr &data) const;
+	const AtNode::Ptr unsetChild(const char* key) const;
 	const AtNode::Ptr addOverlay(const AtNode::Ptr &data) const;
 	const AtIter getChild(const char* key) const;
 
Index: ps/trunk/source/tools/atlas/AtlasObject/AtlasObjectImpl.cpp
===================================================================
--- ps/trunk/source/tools/atlas/AtlasObject/AtlasObjectImpl.cpp
+++ ps/trunk/source/tools/atlas/AtlasObject/AtlasObjectImpl.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2019 Wildfire Games.
+/* Copyright (C) 2021 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -182,6 +182,14 @@
 	m_Node = m_Node->setChild(key, AtNode::Ptr(o));
 }
 
+void AtObj::unset(const char* key)
+{
+	if (!m_Node)
+		m_Node = new AtNode();
+
+	m_Node = m_Node->unsetChild(key);
+}
+
 void AtObj::setBool(const char* key, bool value)
 {
 	AtNode* o = new AtNode(value ? "true" : "false");
@@ -287,6 +295,13 @@
 	return AtNode::Ptr(newNode);
 }
 
+const AtNode::Ptr AtNode::unsetChild(const char* key) const
+{
+        AtNode* newNode = new AtNode(this);
+        newNode->m_Children.erase(key);
+        return AtNode::Ptr(newNode);
+}
+
 const AtNode::Ptr AtNode::addChild(const char* key, const AtNode::Ptr &data) const
 {
 	AtNode* newNode = new AtNode(this);
Index: ps/trunk/source/tools/atlas/AtlasUI/ScenarioEditor/Sections/Player/Player.cpp
===================================================================
--- ps/trunk/source/tools/atlas/AtlasUI/ScenarioEditor/Sections/Player/Player.cpp
+++ ps/trunk/source/tools/atlas/AtlasUI/ScenarioEditor/Sections/Player/Player.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2019 Wildfire Games.
+/* Copyright (C) 2021 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -861,7 +861,7 @@
 			player.set("Civ", str->GetData());
 		}
 		else
-			player.set("Civ", playerDefs["Civ"]);
+			player.unset("Civ");
 
 		// color
 		if (controls.color->IsEnabled())