AfloatX is described as 'An alternative to Afloat that lives in the dock icon menu. Although AfloatX has some of the same features as Afloat, it is not meant to be a clone. AfloatX is a simple and unobtrusive plugin made to add some additional window management features'. There are three alternatives to AfloatX for Mac and SIMBL. The best alternative is PiP for Mac, which is both free and Open Source. Other great apps like AfloatX are Afloat (Free, Open Source) and LayerX (Free, Open Source).
Clone any visibile window Crop the preview Auto and manual resize preserving the aspect ratio Multiple window preview from same process, cmd+n to open and cmd+w to close Pinch to zoom Click-through Opacity control
Keep windows afloat (heh) on top of all others. Pin windows to the desktop. Move windows from anywhere, not just the title bar. Turn a window into an "overlay" on your screen that doesn't hinder your work.