# Layer

A pure PoPo instance has 9 layers, the panel is on the sixth level, and the created panel layout is on the eighth and ninth levels, as follows:

|Type|Layer|Note|
|-|-|-|
|Container|1|Instance mount container|
|Zoom Pane|2|Zoom Pane|
|Zoom Container|3|Zoom container|
|Main Pane|4|Instance Pane|
|Main Container|5|Instance Container|
|Panel|6|Panel Pane|
|Panel Container|7|Panel container|
|Head|8|Head container|
|Lcr Container|8|The left side of the panel, the middle, the right area container|
|Foot|8|The container at the bottom of the panel|
|Left|9|The container at the left of the panel|
|Center|9|The container at the center of the panel|
|Right|9|The container at the right of the panel|

- Schematic diagram of hierarchy relations

![layers1](../_images/layers2.png)

- Hierarchical topological graph

![layers2](../_images/layers.png)