How to work with Merge in layer menu
To work with Merge in layer menu
You can combine multiple layers together to create merged layers. The merged layer contains all of the data from the source layers and bases its appearance on their blend modes. All vector data in the source layers will be converted to raster data.
Merge layers in one of the following ways:
Merge all the layers to produce a flat image by choosing Layers > Merge > Merge All (Flatten) or right-clicking a layer in the Layer palette and choosing Merge followed by Merge All (Flatten) from the pop-up menu.
Merge only the visible layers by choosing Layers and then select Merge. AFter that click Merge Visible or right-clicking a layer in the Layer palette and choosing Merge followed by Merge Visible from the pop-up menu. The hidden layers are not affected.