Lock order or sort documents in Aggregation Pipeline Builder's preview area
When we create a pipeline, it'd help if we could check the same documents data in the different stages ( now their preview is from randomly selected documents AFAIK ), so it's inconvenient to inspect one specific documents preview phases through all the stages.
1) lock the first stage's documents' order and apply it to the following stages (if possible, eg. if the stage is $group, then we can not apply the rule to the next stage)
2) set a sorting ( if possible ) of documents. But only for the preview.