Activities are the defining feature of the KDE 4 release series. Super-charged virtual workspaces, each of which can also contain its own virtual workspaces, Activities are by far the easiest way to increase the available desktop space, and to work with a task-oriented rather than an application-oriented approach.
Yet, despite their potential, Activities remain poorly understood. Part of the problem is a lack of explanations, or use-cases. Another part is a lack of easy-to-use tools.
As a result, even those who have discovered Activities on their own take longer than necessary to make full use of them. Many users fail to see the point in them, and either stick with virtual workspaces alone, or choose more costly and complex solutions such as multiple monitors.
To be fair, improvements have been made since the first KDE 4 releases. The current KDE 4.9 release candidate, for example, cleans up the configuration display for Activities. It also allows files and windows to be set to open in selected Activities, which reduces desktop clutter and helps to assure that the specialized widgets need for a particular app are always available.
But although such changes are welcome, they're coming too slowly. At this rate, it will be KDE 4.19 before Activities are what they should be. Here is my wish list of improvements that would help Activities to come into their own:
You can easily state the relationship between Activities and virtual workspaces. When used as intended by the developers, Activities are organized by tasks, and use virtual workspaces to organize the work of the moment.
However, the desktop itself fails to make the relationship clear. There is neither a pager nor any task manager setting that shows virtual workspaces as subordinate to Activities. Instead, virtual work spaces have their own pagers, and Activities are only displayed when you select Activities from the desktop toolkit.
This arrangement is convenient for those who only want to use virtual workspaces. However, it makes Activities easy to ignore and -- because they are harder to access -- makes them seem redundant to the uninitiated.
Moreover, it makes switching to a particular workspace of a particular Activity harder than it should be when the workspace has no open windows. First, you need to switch to the Activity using one set of tools, then to the work space using another set of tools. There is no way to switch to the work space directly.
Throughout the KDE 4 release series, developers have struggled with the best way to display Activities. For the first few releases, the choice was an overview similar to GNOME 3's. For the last few releases, the choice has been a horizontal scrolling window that is stuck in position at the bottom of the screen. An Activity Bar widget is available, but remains strangely slow to respond to mouse-clicks.
The most successful switcher I have seen for Activities is the spinner rack in Plasma Active, the KDE desktop environment for tablets and other mobile devices. Unobtrusive yet easy to access, it is such an improvement over the other displays that you have to wonder why it hasn't been generally implemented throughout KDE.
When you add an Activity, you have the option of basing it on a Template. The trouble is, nothing explains the features of the available templates. Most users can only guess what a Grid or Grouping Desktop might be, or what Newspaper Layout might be without trying them first. More likely, users will choose the safer-sounding Empty Desktop, and never learn the possibilities of the templates.
Nor does the desktop include any utility for creating your own templates. The most you can do is clone the current Activity.
Should you want only a particular feature of another template, how do you add it? In particular, if you notice that the Desktop icon template allows you to set applications to run when you switch to the Activity, how do you duplicate that feature on a different template? How do you change the applications to run?
For that matter, how do you use the existing dialog for adding the applications to run? I don't know about anyone else, but I'm still unable to use it (and the problem isn't that I haven't tried)
Such problems make Activities far harder to customize than they should be -- which weakens one of the main points of using Activities in the first place.
When you log into KDE, the desktop opens on the last Activity you were using. Short of changing to the desktop you would like to log in with next time at the end of every session, there is no way to set the default Activity.
Users can add a custom icon to an Activity to make it more immediately recognizable. Yet, so far, no one has developed an icon set specifically for Activities. Instead, you have to customize with the same selection that is available for desktop launchers, and use your own ingenuity.
For example, you could use the icon for the digiKam photo manager for an Activities called Graphics, or the icon for KPat for an Activities called Games. Very likely, though, you will have to scroll through dozens of icons to find a suitable choice. Why not have a filter of several dozen general purpose icons, representing common activities?