Make order list more friendly to shop managers => filter out orders in "AddingItems" state

[chladog]

Is your feature request related to a problem? Please describe.
There is going to be huge amount of never completed orders that just stay in AddingItems state forever.
Even though those data are valuable for analytics of customer behavior, on ordinary day those are not orders that interest shop managers who need clear list of orders in the process be it payment states, custom states, partial fulfillment etc...
Current filter filters only by one specific state.

Describe the solution you'd like
Allow the current filter to take multiple selects (e.g. multiselect list with checkboxes)
This setting should be persisted per user.

Describe alternative you've considered
A filter that can filter out any state (meaning all states except those in filter are present).

Describe addition you've considered
Some mechanism of tidying anonymous orders that never make it out of "AddingItems" every once in a while

[chladog]

Additionally custom order states are not present in current filter. Those we would like to have in this new filter implementation present as well.

[incorvia]

I think a general solution that could allow a developer to implement custom filters of varying types against custom fields would be ideal as a long term goal. I come from a Rails background and use ActiveAdmin quite a bit. One can quite quickly create a filter against a specific column by defining some backend setting like:

filter :email, as: :string

Resulting in a filter like:

I imagine a tool similar to how one can create custom promotion conditions would be amazing.

[michaelbromley]

I have implemented improved filtering in the order list view in the above commit.

Some mechanism of tidying anonymous orders that never make it out of "AddingItems" every once in a while

This setting should be persisted per user.

a general solution that could allow a developer to implement custom filters of varying types against custom fields

These are all great suggestions but for the sake of keeping this issue focused, I am considering them out of scope for now. Please feel free to open individual feature requests for the above (I'd say only the first one is something I'd prioritize for v1.0)