Merged size-color diagram, combining observations (Fig. 4) with the model population (Fig. 5). In gray, we indicate the range of models without a gap. In yellow, we show the approximate range of models with a gap between the inner halo and the disk component. We note that both regions indeed overlap. Group Ib sources with colors deferring from the model population are V1247 Ori (#14), HD 135344 B (#39), Elias 2–30 (#51), and HD 169142 (#59).