not sure what is causing your issue but i made a quick 30+ layers (see screengrab) - i'm thinking it may be a file size issue. How big is the working file? Down by the lower scroll bar there is a drop-down arrow that you can select to see a bunch of different stuff. I usually have mine set to view document size (this tellls me how big the working file is getting)

 

also do you have the AUTO-SELECT option (in the top tool bar) selected for Layer?  that helps me to quickly select the layer i want to work on regardless where it is in the palette.

 

hope this helps, let me know

scott