A Silex publication, whatever kind, is made up of layers and sub-layers (if you know Photoshop and Illustrator for example, it is the same principle).
Each layer has necessarily one sub-layer. You can’t dissociate them.
Here <start> is a layer and “fade”, just under, is its sub-layer. <template_import_pdf_first_page> is also a layer and “fade”, just under, is its sub-layer.
A layer (most of the time) corresponds to a page of your publication.
When you edit a publication, you must add the different components on the sub-layer. Anyway, it’s impossible to add components on a layer.
When you select the sub-layer, you can see all the components that it contains and have the option to add others.
When you select the layer, there is nothing in the components toolbox and you can’t click “add component”.
Sometimes, a layer can have several sub-layers:
Here <start> has 2 sub-layers: under and over.
The advantage of having several sub-layers for one layer is essentially a better organization of your components. In fact, if you have lots of components on a layer, it’s interesting to dispatch them.
Note: the number of sub-layers for one layer depends on the layout chosen to open your layer.
Add a layer
Look at the article “Silex Page creation”
Delete a layer
If you want to delete a layer, select it and click on the trash. It will automatically delete all the sub-layers related to it.
Note: you can’t delete sub-layers directly. If you want to delete a sub-layer, you must delete its layer.
Note 2: The <start> layer is a bit particular.
* It’s the first layer of your publication and you can’t avoid it!
* You can’t delete it.
* All the components that you put on its sub-layer will be visible on all the pages of your publication.
* It corresponds to the level 0 on the layer’s depth and it is the one and only. It cannot be other layers as the same level as him.
* You can rename it via the <Manage> section in your publication’s properties.
* You can change its layout via the <Manage> section, in your publication <Advanced> section and the on the <Layout> section
Note: in the case of the <start> layer, the layout is important to define its number of sub-layers.
This concludes understanding the Layer/Sub-Layer concept in Silex