Hide my Windows is described as 'HMW is a free program to hide away the Windows on your desktop. With HMW you can set any program Window as hidden, while the program itself will run silently in the background. Additionally all the Hotkeys used can be customized to your needs' and is an app. There are 2 alternatives to Hide my Windows for Windows, Linux, PortableApps.com and X11. The best Hide my Windows alternative is Clicky Gone, which is both free and Open Source.
Clicky Gone allows you to hide your selected windows from view, this includes the taskbar button associated with the application. This utility particularly helps with protecting your privacy by hiding things like your browser with banking details up and someone walks in on you.
Clicky Gone is the most popular Windows alternative to Hide my Windows.
Clicky Gone is the most popular Open Source & free alternative to Hide my Windows.
A small program to show and hide windows in X window system. Most Linux distributions use a display server with X window system, you can easily hide and show windows using this program.
mapmywindows is the most popular Linux alternative to Hide my Windows.
It is directly inspired by this program and has similar functionality. It aims to provide a good alternative for linux (and potentially other unix users)