When using MATE Tweak to switch the interface panels in Ubuntu MATE 16.04 Beta 1, the drop shadows for the panels inconsistently load. Sometimes they appear, and sometimes they do not. You may have to switch Panel layouts (i.e., switch between Mutiny and, say, Fedora, but any will do) several times before they appear. Also, the drop shadows for the panels can disappear upon logging out or rebooting. To get them back, you have to switch between Panel layouts with MATE Tweak until they reappear again.