RectLayer *layer = undo_context->element.layer;
dynarray_insert_before(layer->rects, undo_context->element.index, &undo_context->element.rect);
dynarray_insert_before(layer->colors, undo_context->element.index, &undo_context->element.color);
RectLayer *layer = undo_context->element.layer;
dynarray_insert_before(layer->rects, undo_context->element.index, &undo_context->element.rect);
dynarray_insert_before(layer->colors, undo_context->element.index, &undo_context->element.color);