diff --git a/src/ai/ai_gui.cpp b/src/ai/ai_gui.cpp
--- a/src/ai/ai_gui.cpp
+++ b/src/ai/ai_gui.cpp
@@ -575,9 +575,10 @@ private:
 	bool IsEditableItem(const ScriptConfigItem &config_item) const
 	{
 		return _game_mode == GM_MENU
-			|| ((this->slot != OWNER_DEITY) && !Company::IsValidID(this->slot))
-			|| (config_item.flags & SCRIPTCONFIG_INGAME) != 0
-			|| _settings_client.gui.ai_developer_tools;
+		    || _game_mode == GM_EDITOR
+		    || ((this->slot != OWNER_DEITY) && !Company::IsValidID(this->slot))
+		    || (config_item.flags & SCRIPTCONFIG_INGAME) != 0
+		    || _settings_client.gui.ai_developer_tools;
 	}
 
 	void SetValue(int value)
diff --git a/src/game/game_gui.cpp b/src/game/game_gui.cpp
--- a/src/game/game_gui.cpp
+++ b/src/game/game_gui.cpp
@@ -442,7 +442,10 @@ struct GSConfigWindow : public Window {
 private:
 	bool IsEditableItem(const ScriptConfigItem &config_item) const
 	{
-		return _game_mode == GM_MENU || (config_item.flags & SCRIPTCONFIG_INGAME) != 0;
+		return _game_mode == GM_MENU
+		    || _game_mode == GM_EDITOR
+		    || (config_item.flags & SCRIPTCONFIG_INGAME) != 0
+		    || _settings_client.gui.ai_developer_tools;
 	}
 
 	void SetValue(int value)
diff --git a/src/settings_type.h b/src/settings_type.h
--- a/src/settings_type.h
+++ b/src/settings_type.h
@@ -187,7 +187,7 @@ struct GUISettings {
 	uint8  developer;                        ///< print non-fatal warnings in console (>= 1), copy debug output to console (== 2)
 	bool   show_date_in_logs;                ///< whether to show dates in console logs
 	bool   newgrf_developer_tools;           ///< activate NewGRF developer tools and allow modifying NewGRFs in an existing game
-	bool   ai_developer_tools;               ///< activate AI developer tools
+	bool   ai_developer_tools;               ///< activate AI/GS developer tools
 	bool   scenario_developer;               ///< activate scenario developer: allow modifying NewGRFs in an existing game
 	uint8  settings_restriction_mode;        ///< selected restriction mode in adv. settings GUI. @see RestrictionMode
 	bool   newgrf_show_old_versions;         ///< whether to show old versions in the NewGRF list