Factorio Forums

It's not possible to open or modify the inventory of player 1 in the editor.

This works:
This just shows a recipe browser or the editor inventory (depending on the active tab like 'None' or 'Tiles'):

Thanks for the report. The inventory of player 1 is you - what you see when you select the "none" editor and press the open-inventory hotkey.

There is currently no way to view the character inventory while in the map editor. I do have plans to make that a thing but right now you just can't.