The Layer Stack shows you where your clips are in VJamms' 16 visual layers

As clips are triggered in the default 'triggered to front' mode you will see them jump to the top of the layer stack. Whatever is at the top of the layer stack will appear over the other clips in your VJamm composition. Drag clips up and down the layer stack to move them around your composition's layers. If you switch triggered to front off you will be able to compose your layers fully and save these modifications in your VJamm patches.

To the left of the clip thumbnails in the layer stack you will see a visual indication of the lumakey and opacity settings of each clip. This helps to visualise the layers of your composition.