The left mouse button in wmx (a window manager) is bound to its unique window selection menu. This is the only way to get at a hidden ("iconified") window, which take up otherwise 0 pixels!

Hidden windows appear first on the menu, and are left justified; after them appear all visible windows, right justified. Of course, just the name of the window isn't enough to know if that's the one you want (this is a problem with window lists in many window managers). So wmx shows you the window the pointer is pointing to, by showing you the two lines comprising its frame (border), along with its (vertical) title bar. It's almost spooky to see your hidden windows appearing in this manner, but it works well. And if you linger for a second, the entire window is mapped in, to show you what it would look like. Selecting a window maps it in in a more permanent fashion (if it was hidden), and puts it on top.

Simple, elegant, and supremely functional, the wmx window selection menu does its job (and nothing more).