Scroll on Dock Icons to Show App Windows (Hidden Mac Trick)

Here's a Dock feature Apple built, shipped, and never mentioned: scroll up on a Dock icon and that app's windows spread out in App Exposé — every window visible and clickable, without touching the keyboard or clicking anything. The same gesture flicks stacks open. It's off by default and absent from System Settings; one Terminal command turns it on. Works on Ventura, Sonoma, and Sequoia.

Enable scroll-to-open

In Terminal (Applications → Utilities), run:

# enable the Dock scroll gesture
defaults write com.apple.dock scroll-to-open -bool true
killall Dock

The Dock restarts in about a second and the gesture is live immediately.

What you can do with it

• Scroll up on a running app's icon — two-finger swipe up on a trackpad, or wheel-up on a mouse — and App Exposé opens: all of that app's windows tiled in front of you, plus recent documents for many apps along the bottom. Click a window to jump to it, or scroll down / press Esc to back out.
• Scroll up on a stack (a folder on the right side of the Dock, like Downloads) and it springs open in its fan or grid view without a click. Scroll up again — or click elsewhere — to close it.

The payoff is speed on window-heavy apps: a browser with nine windows, a Finder with five. Instead of clicking the icon (which raises all windows) or right-clicking and reading a menu, you flick upward over the icon and pick the exact window visually.

Turn it off

# disable the gesture
defaults delete com.apple.dock scroll-to-open
killall Dock

That's the complete undo — the key vanishes from the Dock's preferences and scrolling over icons goes back to doing nothing.

Gesture etiquette: what it won't disturb

Reasonable worries, answered:

• Scrolling over an app with no open windows does nothing — the gesture only fires when there's something to show.
• It doesn't hijack normal scrolling. The gesture only registers with the pointer directly over a Dock icon, somewhere your scroll wheel has no other job.
• It coexists with the standard App Exposé trackpad gesture (swipe down with three fingers, if enabled in System Settings → Trackpad → More Gestures). The Dock version is per-icon and works with any mouse — including third-party mice whose wheels otherwise do nothing useful over the Dock.

Check whether it's already on

Setting up a new Mac from a dotfiles script, or inherited a machine with mystery tweaks? Query the key:

# prints 1 if enabled; errors if never set
defaults read com.apple.dock scroll-to-open

An error saying the pair “does not exist” just means the default state — off. Like all com.apple.dock tweaks, the setting is per-user and survives restarts and macOS updates until you delete it.

Where it fits in a window-juggling kit

Scroll-to-open slots between the tools you already have, each with its own niche:

• Cmd+Tab switches apps — fastest when you don't care which window.
• Dock scroll-up picks a specific window of a specific app — one gesture, visual choice.
• Click-and-hold on a Dock icon does the same via a menu listing window titles — better when windows look alike, since Exposé thumbnails of nine near-identical documents are hard to tell apart.
• Mission Control shows everything from every app — the wide-angle view.

The Downloads stack gets a quiet upgrade too: flick upward over it, glance at the newest arrivals in grid view, flick down to dismiss — the whole check takes under a second and never opens a Finder window.

More gesture mileage

If this sold you on App Exposé, give it a dedicated trackpad gesture too — App Exposé on Mac covers the swipe and its settings.