Afloat is a great program for the Mac that allows one to keep certain windows on top of everything. Available at the MacUpdate for free. This app allows you to change the transparency of a window along with other management tools. I have used this app many times in checking items and keeping a list on the forefront. The always-on-top feature is awesome. Works great, try it out. For more information check it out MakeTechEasier, Life Hacker, or on Afloat website.