[Solved]-How to know if a Scala file modified with IntelliJ Idea is saved and if it is checked into CVS?-scala

If a file is modified but not saved, there's an asterisk, *, in its tab.

If a file is newer than its VCS counterpart, its name is displayed in dark blue instead of black. If it is not under VCS at all, it is shown in dark red. This goes for the editor tab as well as other places such as the Project window.

Under Settings -> IDE Settings -> General -> Synchronization you can control when files are saved. I save files on Frame Deactivation (that is, switching to another program), and after 60 seconds of idle time.

You should also look at the Local History feature, which is a local VCS for your project, capturing all the individual edits between commits. This allows you to roll back changes that were made by the auto-save feature, which some people find unnerving at first.

In IDEA 11:

Settings->Editor->Editor Tabs->Mark modified tabs with asterisk

UPDATE

In IDEA 15:

Settings->Editor->General->Editor Tabs->Mark modified tabs with asterisk