Trados Studio 2009 - Adding term to termbase
1. Select the source term
2. Select the target term
3. Right click on any selected term and click on Add new term (or assign a shortcut for this via Tools - Options - Keyboard Shortcuts)
4. Click on the auto hide icon (only for the first time you add a term)
5. Click on the Save icon or F12 (for some reason F12 does not work for me and others as far as I know).
6. Move back to your text and continue translation (the add term pane will be hidden automatically).