let’s say I have a filter on, e.g. I’m filtering by the tag “python”. If I click on a link to a card, it’ll pop up in preview whether or not it has the tag “python”. If I then decide to add the tag “python” by editing the card whilst in preview, when I click out of the preview, the card does not show up in the filter view. If I want to see it there, I have to nav away and back, or unapply and reapply the filter. Would be nice if the filter view could be refreshed once the tag is added to the card in preview.
This has since been added. Adding a tag while in preview will add the card automatically to the Filtered Noteboard. Marking this as implemented 
So, I might be missing something based on the above…
When I’m in a filtered view of a parent with child cards, I edited some other cards to add the tag for the filtered view. These (newly tagged) cards do not show up in the filtered view until I refresh the filter.
It could be user error!