This application is very similar to TrayEverything, and in my opinion it is better.
Quoting the application's website on features
Clicky Gone's current features include.
1. Click and Hide by holding down keyboard modifiers
2. Run hidden windows application's in the background, i.e Low priority
3. Toggle all windows to hide and show
4. Boss Key support, hide the active window and mute the sound
5. A fancey menu that shows you all your hidden windows
6. Prevent click hiding on full screen applications, i.e. Games
7. Hide menu on applications caption and taskbar icon
8. Process priority menu on applications caption and taskbar icon
9. Hide windows in system tray or completely from view
10. Prevent stuborn windows from showing up after they are hidden, i.e. a long task completes and the application shows another window from the one you have hidden
11. Transparency Effect
Here follows an explanation quoted from the application website:
Clicky Gone Portable vote your prefrence, and download from the application page here.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.
There is no need to close your applications if they are taking up to much space on your desktop or taskbar. Each window you hide can optionally be placed as a small icon in the system tray for easy recovery.
This very small application can also reduce the load on your computer by running hidden applications in the background so that they do not interfere with the visible ones. You can also manage an applications priority manually by using its system menu, this menu can be found by right clicking on the title bar or the taskbar button.
This utility is so fast, light on system resources and packed with enough window hiding features that it will make hiding windows as normal as minimizing or closing them.