SceneEditor: fixes related to partial refresh

hide/comp/SceneEditor.hx

@@ -402,6 +402,8 @@ class SceneEditor {
 			return;
 		var contexts = context.shared.contexts;
 		var ctx = contexts[elt];
+		if(ctx == null)
+			return;
 		var local3d = ctx.local3d;
 		if(local3d == null)
 			return;

hide/prefab/fx/Emitter.hx

@@ -659,6 +659,10 @@ class Emitter extends Object3D {
 		return ctx;
 	}
 
+	override function removeInstance(ctx:Context):Bool {
+		return false;
+	}
+
 	#if editor
 	override function edit( ctx : EditContext ) {
 		super.edit(ctx);

hide/prefab/terrain/Terrain.hx

@@ -240,6 +240,10 @@ class Terrain extends Object3D {
 		#end
 	}
 
+	override function removeInstance(ctx:Context):Bool {
+		return false; // TODO
+	}
+
 	function getCellCount(){
 		var resolution = Math.max(0.1, cellSize);
 		var cellCount = Math.ceil(Math.min(1000, tileSize / resolution));