'DockDoor' Lets You Preview Windows on the Mac Dock

This free app brings a longtime Windows feature to macOS.

Windows lets you preview a window by hovering your mouse over the icon in the taskbar. The Mac can't do that, unless you install DockDoor. This free and open-source application adds previews to the dock and also gives you a proper Ctrl-Tab keyboard shortcut for switching windows.

DockDoor is simple to install: just download it, drag it to the applications folder, and launch it. You will need to provide both accessibility and screen recording permission to the application in order for it to function. After that, the application will run in the background—you can configure it by clicking the menu bar icon.

Hover over any dock icon and you will see a real-time preview of what's happening in that application. If there are two windows open in that app you will see both windows, and you can click on it to open it. These are all features Windows has had for over a decade that haven't yet made their way to macOS.

You can also use the keyboard shortcut Ctrl+Tab to cycle through all windows open on the current space. This is a great way to jump to a particular window without having to hunt it down with the mouse.

Credit: Justin Pot

DockDoor isn't perfect. It can't preview hidden windows, or windows on another space, due to limitations in how macOS operates. If you're a single-space-full-of-windows kind of person, and you miss the window preview from Windows, DockDoor just might be perfect for you.