Ability to hide "Clear completed"

[whatthegit]

Feature details

Firstly, thanks for this app! I would like to request to have an option to hide "Clear completed". This is because I kept clicking on it, but during times when there are many failed encodings within some deep folder structure. Hence, I lost track of which files failed. Even though I know the filenames for such files will include the word "failed", I think it might be good to have this option.