+++ This bug was initially created as a clone of Bug #676566 +++
+++ Reason for cloning instead of commenting: Rise of severity which is not possible by mere commenting +++

Originally from http://bugs.debian.org/673898:

1. Open a non-XCF image, say foo.png.
2. Export the image as foo.png
3. Note that window title becomes "Untitled (exported) ..."

According to http://gui.gimp.org/index.php/Save_%2B_export_specification:
"After a successful export, if there is nodocument–to–file association,
the title of the image window shall be set to “[<filename>] (exported)-X.Y etc, etc.” where the <filename> is the name (minus extension) of the file exported to;"

According to the spec, the window title at this point should really be "foo (exported) ...";

+++ Additions to cloned bugreport +++

Severity: 

Promotion to normal: It is very important to know to which filename the image is saved by pressing ctrl-e. Otherwise important files (versions before experimantal changes) may be overwritten (and hence lost) unintentionally.

Filename-Extension in title bar (was working in Gimp 2.6): 

Picture.jpg is loaded. Title bar shows only [Picture]. There may be different versions: Picture.jpg, Picture.xcf, Picture.png. It is intended to load the jpg, not xcf or png. So the title bar should show the complete filename (Picture.jpg) for confirmation (as was the case with Gimp 2.6). Also after export it is important to know to which format (jpg, png, ...) the file is saved by future Ctrl-E commands
If the title bar shows Picture.jpg the user knows: Ctrl-S will save Picture.xcf, Ctrl-E will save Picture.jpg.