The old Gimp versions (before 2.7) had only 1 "save" dialog.
The user could choose to save as XCF or any other format, either by selecting a format from the drop-down, or by specifying an extension manually.
since 2.7, novice users will save always in XCF, but then power users like me have to use different set of key-binding and different dialogs for each type of save, and it's both annoying and cumbersome.
Is there any setting or trick to use the same save-as dialog for ANY file type, like it was before??