You have four Safari windows open. One has the documentation you need, one has the project reference, one has a StackOverflow thread, and one has your email. You click the Safari Dock icon. All four windows stack in front of you and you click through them one at a time looking for the right one. Every time.
This is a solved problem on Windows and Linux, where taskbar hover previews have existed for years. macOS has never had it natively. Dockspace adds it.
The Multi-Window Problem
Modern Mac workflows generate a lot of windows. A developer might have three terminal sessions, two browser windows, an IDE, and a Slack window. A designer might have multiple Figma files, reference images in Preview, a browser for inspiration, and a notes window. A writer might have multiple research tabs, the actual document, and a reference PDF.
macOS's native tools for managing this are Mission Control and Cmd+Tab. Mission Control shows everything at once — useful for orientation but expensive to invoke (takes over the screen). Cmd+Tab cycles through apps, not windows — if you have four browser windows, Cmd+Tab gets you to Safari, then you still have to figure out which window to bring forward.
The gap is targeted window switching: "I want this specific Finder window, not just Finder." Window previews in the Dock fill that gap precisely.
How Dockspace Window Previews Work
Hover your cursor over any app icon in the Dock. After a short configurable delay, a preview card appears above the icon showing thumbnails of all open windows for that app. Thumbnails are live — they show current window content, not stale captures. Click any thumbnail to bring that window to the foreground.
The previews use macOS's CGWindowListCreateImage API — the same API used by Screenshot.app —
to capture window content efficiently. Captures happen on hover trigger, not continuously, so the system
is not rendering previews you are not looking at.
If an app has only one window open, the preview card shows that one window. If it has ten windows, the card shows a scrollable grid of thumbnails. Window titles appear below each thumbnail for disambiguation.
The preview hover delay is configurable in Dockspace Preferences. Set it to 0ms for instant previews if you switch windows frequently. Set it higher (300–500ms) if you find the cards appearing when you are just moving your cursor across the Dock.
Window Previews vs. Mission Control and Exposé
Mission Control (three-finger swipe up or F3) is powerful but disruptive. It takes over your entire screen, exits full-screen apps, and requires you to mentally scan for the window you want across a zoomed-out overview of everything. It is excellent for spatial orientation — understanding where all your windows are — but poor for targeted switching when you already know which app you want.
App Exposé (three-finger swipe down, or right-click a Dock icon → Show All Windows) shows all windows for a single app, which is closer to what window previews do. The difference is context: App Exposé takes over the screen for that app. Dock window previews are a card overlay — your current window stays exactly as it is.
| Feature | Mission Control | App Exposé | Dockspace Window Preview |
|---|---|---|---|
| Scope | All apps, all spaces | One app at a time | One app at a time |
| Takes over screen | Yes, completely | Yes, for that app | No, overlay card only |
| Trigger | Gesture / keyboard | Right-click or gesture | Hover over Dock icon |
| Context preserved | No | No | Yes — current window unchanged |
| Click to focus window | Yes | Yes | Yes |
| Speed | Medium | Medium | Fast (no mode switch) |
Window Previews vs. Cmd+Tab
Cmd+Tab cycles through applications. It does not cycle through windows. If you want a specific window in an app you already have focused, Cmd+Tab is not the right tool — you need to use Cmd+` (backtick) to cycle through windows within the current app, or use Mission Control.
Dock window previews short-circuit this entirely. You see all windows for any app on hover and click directly to the one you want, regardless of what is currently focused.
Apps Where Window Previews Shine Most
Safari / Chrome / Firefox
Browser windows multiply faster than any other app. Docs, tools, references, personal tabs — most people have 3–8 browser windows open at any point. Window previews let you see which one has the content you want before clicking.
Finder
Multiple Finder windows are common — Downloads, project folder, external drive, and wherever you last used Save As. The window preview thumbnail shows the folder you are looking at, so you can navigate directly without cycling through Finder windows.
Terminal / iTerm2
Developers often run several terminal sessions simultaneously — one per project, one for a long-running process, one for git. The preview card shows each terminal's current content, making it easy to spot the session you want.
Notes / Obsidian / Bear
Writing apps sometimes have multiple documents open. Preview thumbnails show enough text to identify the right note quickly.
Enabling Window Previews
- Install Dockspace from getdockspace.app.
- Open Preferences from the Dockspace menu bar icon.
- Enable Window Previews in the Widgets or Features section.
- Optionally configure hover delay, thumbnail size, and whether to show window titles.
- Hover over any Dock icon to see previews immediately.
No permissions beyond Accessibility are needed. Dockspace requests Accessibility access during initial setup — this is required for it to read window information from other apps.
Stop guessing which window is which. Dockspace window previews are free.
Try Dockspace FreeTo see how window previews compare with what DockDoor offers, read our Dockspace vs DockDoor comparison. For the full picture of Dockspace's widget suite, see the best Mac Dock widgets guide.
Frequently Asked Questions
Do window previews show real-time window content?
Yes. The preview captures current window content at the moment you hover. If you have a video playing in a window, the thumbnail reflects that. Captures are fresh on each hover.
Can I use window previews with apps in different Spaces?
Window previews show all windows for an app, including those in different Spaces. Clicking a preview for a window in another Space switches to that Space automatically.
Do window previews work in full-screen mode?
When you are in full-screen mode, move to the bottom of the screen to reveal the Dock. Hovering over icons in the revealed Dock triggers window previews as normal.
What is App Exposé and how is it different?
App Exposé (available via three-finger swipe down on the trackpad, or right-click a Dock icon → Show All Windows) is a built-in macOS feature that scales out windows for a single app. Unlike Dockspace's preview cards, it takes over your current view and requires an intentional gesture.
Do window previews work with minimized windows?
Yes. Minimized windows appear in the preview card and can be clicked to restore them, which is faster than looking for their thumbnails in the Dock's right section.
Is this feature available in the free tier?
Window previews are available in the free tier of Dockspace. The Pro upgrade adds customization options such as thumbnail size and animation style.