The user should be able to revert temporary modifications and get the current translation for a message he started editing.
This functionality can be provided by adding an "insert button" similar to the "copy from source" one. The new button would be labelled as "Revert to previous translation" and will be only visible for messages that already have a translation under the following circumstances:
- The user deletes the translation text.
- The user open an "unsaved" message.