Lots of people are complaining that, in OS X El Capitan, Mission Control doesn’t show thumbnails of fullscreen apps and/or desktops along the top of the screen unless you place the mouse cursor there, in which case they slide into view. Instead you get a horizontal text listing of the apps/desktops.
Previously in OS X the thumbnail list was always visible. See the screenshot below for an example showing Yosemite vs El Cap:
I can’t offer a full fix for this problem but there are a few tricks that you can try to work into your workflow.
Start Mission Control by bashing
In El Cap, Mission Control will start when you click and drag any window into the top of the screen. This will also display the thumbnails, because Mission Control is expecting you to make the app you’re dragging full screen.
However, if you subsequently drop the window you’re dragging onto the main Desktop thumbnail, Mission Control will let you select a different window at your leisure. Note that for this to work effectively you’ll need to bash the window into the top of the screen from some distance away.
You can make it so that bashing the mouse cursor into the left and/or right-hand corner of the screen starts Mission Control. Because the mouse cursor is already at the top of the screen, the thumbnail bar will be visible. Here’s how to set this up:
- Open System Preferences and click the Mission Control icon.
- Click the Hot Corners button at the bottom left, and for the top left and/or right corners set the dropdown list to read Mission Control. Then click OK.
Now bash your mouse into the top left or right corner of the screen, and Mission Control will activate complete with thumbnails on view.
Use an external monitor
Rather oddly, if you have an external monitor attached AND you’re running an app full screen on that monitor, then the thumbnail bar will always appear whenever you enter Mission Control. One way to do this easily and fuss-free would be to use an app like Duet to create a separate desktop on your iPhone or iPad, and run any app full-screen on it (it obviously doesn’t matter which). You then can put your iPhone or iPad down and ignore it.
Setup LOTS of fullscreen windows
Even more oddly, if you have LOTS of windows switched to full-screen — as in around 14 — then Mission Control will switch back to showing thumbnails. These zillion windows can be all the same app — perhaps 14 empty TextEdit documents, as an example — or they can be different apps. However, I’m not sure if this doesn’t defeat the purpose of having thumbnails visible, however, because it gets very confusing as to what app is where in the listing. It also consumes your Mac’s resources, of course.