Afloat!

A lightweight application that provides a real-time thumbnail replica of any window of your choice. OnTopReplica will stay always on top, allowing you to keep track of the original window while working and without having to keep the keyboard focus on it. You may also crop regions out of the original window, for instance removing GUI elements from your video player or browser, thus allowing you to watch movies or youtube videos in a corner of your monitor while working.

DeskPins can be used to make any application topmost, that is, to keep it above all other windows. Just grab a pin from the DeskPins icon in the system notification area (a.k.a. taskbar tray) and click on any window. This functionality is identical to the "Always on Top" setting found in some programs. With DeskPins you can add this feature to any program!

Set a window to stay on top with this single-function but handy application.

Duplicate Windows visually copies any window in Mac OS X live and on-the-fly. It’s like display mirroring for individual windows! I created the tool to display windows across multiple monitors in extended desktop mode during presentations. It’s proven useful to watch web videos over other windows as demonstrated below, or to keep an eye on windows I’m not actively using. I’m certain that there are yet undiscovered uses for such Duplicate Windows.

An intuitive app to display transparent images on screen.

Nail It is an ancient but tiny utility that lets you make any window stay on top of other windows temporarily.

"Window On Top" is a small gadget made by Compzets.com which keeps any specific window on top of other windows. It does not have any user-interface (UI), it just sits on your tray bar and works with only a single keyboard shortcut.

What Overlay2 does

WindowWatcher is a free hybrid window magnifier and remote control spy. It gives Windows the ability to have proper and resizable picture-in-picture support above and beyond Aero Snap. It's great for watching stuff like online TV, streams or Youtube playlists in a small corner of your workspace while working in the rest of it. It's also a fantastic help for tasks that would otherwise require flicking back and forth between windows, or to provide a simple pop-out viewer for websites and apps that don't have their own. »

With the Uberlayer app you can put floating images on top of your computer screen. Maybe you want to proof a design to the pixel, watermark a presentation or always have that special picture of your mother on top?

Turn any mockup into a floating guide, and visually align pixels with ease.

This extension helps develop your websites with per pixel accuracy!Extension for web developers and markup designers.