activity 和 desktop的差别

Plasma 中引入了 activity 的概念，虽然多个activity 和 desktop 从表面看起来差不多，但还是有很大的差别的。以下摘自 suse 的帮助文档，不翻译了。

Plasma 的组成：
The essence of Plasma revolves around two basic concepts: Plasma Widgets and Containments. Widgets is Applets, or small applications that live on the desktop. Containments is Applets that act as the container for the Plasma widgets
On a default desktop, there are two main elements: the Panel and the Desktop itself. Both are containments in the Plasma sense.

Plasma 和 desktop 的差别：
The desktop toolbox, accessed via the top right corner has a button for displaying your activities, of which Plasma allows you to have more than one. Basically, that is multiple desktop containments hosting multiple sets of Plasma widgets. Display the “Activities” bar, choose Add activity to create a new containment, select your new containment and customize suiting your taste. Plasma’s activities and KWin’s desktop grid are similar in that respect, but there is a fundamental difference. While virtual desktop are used to group and organize windows, Plasma’s activities are used to group and organize Plasma widgets. This way, you can switch between activities and have relevant Plasma widgets supporting the task you're currently trying to accomplish.