Hello lb01cn,
first of all: loop viewer is working well. If you select "independent", you do not need to add anything meaning the strategy would trade.
If you select "Generate only Signals" the strategy do not trade and just uses the signals until the necessary blocks are added (pending open, open at market).
If you have further questions please post them in "Knowledge Base" so that the community as well as the support from Dukascopy can answer your questions.
Maybe for understanding the loop viewer you can watch the webinar in youtube
https://www.youtube.com/watch?v=2i993oVT4XU as well as the other videos if you want to have some examples.
Kind regards