Unfortunately the auto-propagate direction (as it is in Studio) is not yet available in Online Editor. the 2 settings Confirm segment after auto-propagating an exact match and Auto-propagate exact matches to confirmed segments are the only ones available at the moment in Online Editor.
We would need to configure auto-propagation either in the file or the project settings such as in Trados Studio. Auto-propagation should prompt the user and show the segments that are affected by auto-propagation which does not seem the case at the moment.