Tab Bar:

Each view has (by default) its own tab bar. The tab bar allows you to select between different documents, and arrange them. For the tab bar configuration options, see Preferences.
The tab bar shows for each file its name and a little icon indicating the status of that file. A blue disk (

) means the file is not modified (or it is a new document). If the disk is red (

) it means that the file has been modified and these changes have not yet been saved. A grey disk (

) means the file is marked as read-only and cannot be modified (see Read-Only).
If more tabs are visible than can be shown on the display, two small arrows appear on the right, allowing you to scroll through the tabs to find the correct one.
The active tab can show an orange line (enabled by default). If two views are enabled (see Multi View), the tab with the darker shade of orange is the active one.
You can control the colors the tab bar uses using the Styler Configurator (see Styler Configurator).

You can reach the tab bar context menu by rightclicking on a tab. This context menu allows quick access to certain commands for managing your files, getting and settings file properties and moving the tab to other views.