Ah yes, our Leopard review keeps on marching along! This is the third installment of our Mac OS X Leopard review. For those keeping score at home, here’s what has been covered so far:

• Part 1: The Leopard UI
• Leopard screenshots
• Part 2: Spotlight and the Finder

This part will cover one new Leopard feature that has been the focus of controversy in some circles: stacks. And as usual, the score at the bottom of this page pertains to this section only. We will give Leopard a cumulative score when the review is complete.

Before we get to actually discussing stacks, let’s go back in time…

A brief history lesson

The Dock itself has its roots in NEXTSTEP, where it served as an application launcher and worked much like the Dock in Mac OS X. The idea behind stacks, at least as far as I know, has its roots in an old Mac OS feature: tabbed folders. The idea behind tabbed folders was simple: open a folder in the Finder and drag its window to the bottom of the screen. The window’s titlebar would then become a tab anchored to the bottom of the screen, thus making the folder’s contents accessible with a click. Tabbed folders were well-designed. If you dragged a file to a tabbed folder, the folder would spring open, allowing you to drop the file into the tabbed folder, or into a folder inside the tabbed folder. It was a pretty cool ideas.

Then along came Mac OS X and the Dock.

With Mac OS X, Apple eliminated tabbed folders, but replaced with a very similar feature: the ability to keep folders in the Dock. Docked folders allowed for easy access to a folder’s contents; you could click the folder to open the folder in a Finder window, or click and hold the icon to bring up a menu listing the contents of the folder. The pop-up menu also allowed you to drill down deeper into the file structure via a series of submenus. Again, it was a useful feature, though with a couple notable drawbacks. If you had multiple folders in the Dock, it could become somewhat confusing to tell which was which as there are no text labels until you mouse over the icons. Also, in Mac OS X’s implementation, docked folders were not spring-loaded like other folders in the Finder.

With Leopard, Apple decided to evolve this feature into stacks.

A stack viewed as a fan.

What is a stack, anyway?

At its heart, a stack is nothing special. It is just an ordinary folder dragged into the Dock. Once put into the Dock, the folder loses its regular folder icon, and is instead graphically represented by a stack of documents (hence the name).  Clicking these lovely little piles in the Dock reveals their contents, which fan out over the Desktop. Select an item in a stack and the stack collapses back into the Dock again.

I seem to remember there being some mention that stacks could be created arbitrarily (e.g. any group of files could be dragged into the Dock to form a stack), but this functionality never made it into the final version of Leopard. If someone with more information could tell me if this feature was present in any of the developer builds or if I was imagining it, please leave a comment.

Stacks are spring-loaded; when you drag an item over a stack icon, the stack opens, but in a Finder window. (As a side note, the Dock as a whole is spring-loaded. For example, if I hold an image over the Pages icon for a few seconds, Pages will spring to the front, and I can drop the image into my Pages document.) Additionally, files and folders can be dragged out of stacks and into other folders, into the Dock, or the Trash.

Stacks can be sorted by name, kind, date added, date modified, and date created. Also, stacks can be viewed as a fan or a grid of icons. By default, stacks with eight items or fewer display as a fan and stacks with more than eight items display as a grid. Sorting and viewing options can be accessed by right-clicking the stack icon.

What stacks do well and where they fall short

Stacks make it easy to quickly access the contents of a folder, and since they normally don’t spawn a window, they can help reduce desktop clutter as well. Stacks are also very visual; files in a stack display icon previews when fanned out, and the icons are large enough where most files can be discerned fairly easily (at the least you’ll be able to easily tell apart a text document and image file). Files are clearly labeled as well, so even if you have five text files in a stack, finding the one you want should be easy.

The Downloads stack is particularly useful. When you download a file, the stack icon “jumps” to notify you of the completed download. Additionally, the Downloads stack sorts by date added, and when viewed as a fan, the Downloads stack (and any other stack for that matter) puts the most recently added files closest to the Dock, thus reducing mouse movement.

Stacks has its share of downsides, however. The biggest one is that stacks can only show a limited number of items. Presumably, how many items a stack can display hinges on your screen size. On my MacBook screen (1280x800 resolution), a stack viewed as a fan can display eight files (which is fine for the Downloads stack, where you will most likely be interested only in the most recently added items), and a stack viewed as a grid is limited to 62 items. A scrollbar or even multiple pages would be nice, and would greatly enhance stacks’ usefulness.

When clicked, folders inside stacks open in another Finder window, so it is impossible to drill down through multiple folder levels without opening another window. There is no way I can think of for this to be implemented cleanly in the current incarnation of stacks, though. Lastly, if you preferred the old “menu” method, too bad; you can’t disable stacks and revert back to the previous docked folders concept.

The Dock icons for stacks are a double-edged sword. In some instances, they can make identifying folders in the Dock easier as each of the icons would display different files. At the same time, however, if all you work with are Word files, and you have three stacks full of nothing but Word files, the three stacks will look nearly identical in the Dock.

Worth your while?


I can’t speak for everyone, of course, but for purposes where you don’t have too many items in a folder, stacks are great. I never used docked folders in earlier versions of Mac OS X, but I use stacks. I like the Downloads stack in particular, as I mentioned. I think that the concept of stacks is useful overall, but as I pointed out, there are a few issues that need to be worked out. It’s a new feature, and in time I think most of the flaws will be worked out. For the time being, though, I give this feature a score of 3.0. Stacks are a great idea, and they work great for some purposes, but the implementation needs work.

Articles in this series

• Part 1: The Leopard UI
• Leopard screenshots
• Part 2: Spotlight and the Finder