My filter doesn't seem to be working for my car though.

I'm running Factorio version 0.12.29 and I get the error:
Error while running the event handler: __rope_time__/control.lua:344: Callable only on inserters or cargowagons.

The code for which is:

342: if entity.name == "bed-frame" and ...

Suggestion One:
Filters on inventories other than the cargo wagon and tool bar/hot bar would be super useful for me right now. Not just in the mod I'm working on either. I often find myself wanting to add filters to the car's inventory.

Suggestion Two:
Filter by item category. I've been working on ...