Most perspectives in the PDT are comprised of an editor area and one or more views.
You can associate different editors with different types of files. For example, when you open a file for editing by double-clicking it in one of the navigation views, the associated editor opens. If there is no associated editor for a resource, the PDT will attempt to launch an external editor.
Any number of editors can be open at once, but only one can be active at a time. The main menu bar and toolbar contain operations that are applicable to the active editor.
Tabs in the editor area specify the names of resources that are currently open for editing. An asterisk (*) shows that an editor has unsaved changes.
By default, editors are stacked in the editor area, but you can choose to tile them in order to view source files simultaneously.