Maybe a different workflow would be better for you. Try this workflow to convert the files in a batch:
- Open all the files that you might use for your project in the playlist (File->Open and then select multiple)
- Open View > Resources and select all the files that you want to convert
- Click “Convert Selected”
- When the convert dialog opens, choose your options and click “OK”
- Wait for all the files to convert
- Start editing your project - choosing the converted videos from the playlist