Swap Primary/Translation
Suggestion/Opinion
It may be only my personal preference, but I'd rather use the primary column (left-hand side) for editing and use the translation column only for reference.
Example:
If I get an English script with a request to translate it into German, then I load the English text into "Translation" and type my German text into the left-hand side. This seems to give me more editing options and also allows me to switch the "Translation" off, if I do not find it helpful. (You cannot edit a translation without having a primary file loaded.)
How do other users see this?