With all the special device layers and marking layers, a full-chip layout file can easily have several hundreds of layers. It's painful to go through each one of them to find out what you really need to look at. DESIGNrev provides some functions to ease your pain.
You can sort the panel by drawing order or by layers shown up in the current view. There's a sort button on the upper-left side of the layer panel to enable you to choose different sorting options.
If you select the layers and right click them, you can create a filter with your focus layers. The filter can be applied on the layer panel to show only the layers you want to see.