When you have ported in hundreds of strings in the translation editor, and after translating those that you realise you need, and then want to delete those you don't need, it becomes a laborious task deleting one row at a time.
Can you update your grid to allow for multiline select and delete.
This will speed up matters a whole lot.
Thanks
Adrian
(P.S. I see you cannot select all, but you can use the clear command to clear all.)
Will try to add in next update. Meantime you can just select the range of cells using SHIFT+ARROWS (including identifier column) and press delete to empty them. When leaving Strings section ALL empty rows will be automatically deleted.