// Return an enumerable lits of placed tiles in the given level.
        private IEnumerable <IPropertyObject> GetPropertyObjects(ObjectFindScope scope)
        {
            // Search tile data.
            foreach (KeyValuePair <string, TileData> entry in Resources.GetResourceDictionary <TileData>())
            {
                yield return(entry.Value);
            }

            // Search event tile data.
            foreach (KeyValuePair <string, EventTileData> entry in Resources.GetResourceDictionary <EventTileData>())
            {
                yield return(entry.Value);
            }

            // Search placed tiles.
            if (scope == ObjectFindScope.EntireWorld)
            {
                foreach (Level level in editorControl.World.Levels)
                {
                    foreach (IPropertyObject obj in GetPropertyObjectsInLevel(level))
                    {
                        yield return(obj);
                    }
                }
            }
            else if (scope == ObjectFindScope.CurrentLevel)
            {
                foreach (IPropertyObject obj in GetPropertyObjectsInLevel(editorControl.Level))
                {
                    yield return(obj);
                }
            }
            else if (scope == ObjectFindScope.CurrentSelection)
            {
                // TODO: Current selection.
                //editorControl.LevelDisplay.SelectionGrid
            }
        }
        // Return an enumerable lits of placed tiles in the given level.
        private IEnumerable<IPropertyObject> GetPropertyObjects(ObjectFindScope scope)
        {
            // Search tile data.
            foreach (KeyValuePair<string, TileData> entry in Resources.GetResourceDictionary<TileData>())
                yield return entry.Value;

            // Search event tile data.
            foreach (KeyValuePair<string, EventTileData> entry in Resources.GetResourceDictionary<EventTileData>())
                yield return entry.Value;

            // Search placed tiles.
            if (scope == ObjectFindScope.EntireWorld) {
                foreach (Level level in editorControl.World.Levels) {
                    foreach (IPropertyObject obj in GetPropertyObjectsInLevel(level))
                        yield return obj;
                }
            }
            else if (scope == ObjectFindScope.CurrentLevel) {
                foreach (IPropertyObject obj in GetPropertyObjectsInLevel(editorControl.Level))
                    yield return obj;
            }
            else if (scope == ObjectFindScope.CurrentSelection) {
                // TODO: Current selection.
                //editorControl.LevelDisplay.SelectionGrid
            }
        }