I tried to rebind the Map key from M to a different key using the input.settings file. Opening the map works fine, but closing the map still works with M only, but not with the new key, although not a single occurrance of IK_M is left in the file.

Does anyone know a trick to accomplish that?

*laugh* I was just creating a new Thread:

"I have rebound the 'I' Key (the Inventory) to the 'Y' Key by editing the .setttings file and that works.
However, on pressing 'Y' again, the Inventory doesn't go away.
[Panel Keys (like Inventory, Map, etc) seem to be a toggle, if you follow me, but now this doesn't work.]
The weird thing is, that pressing 'I' again, makes the Inventory screen go away, even though the .settings file has been purged of all " IK_I= " references."

So, the same problem. It's weird that it's still getting the I/M from somewhere, to close the Inventory/Map screen. Maybe this is part of the problem with some things being locked, but editable. It might be glitchy. Sorry I couldn't be of any help. It's not just you though. If I hear/find out anything, I'll let you know.

Edit: I did find:

IK_I=(Action=PanelInv)
IK_M=(Action=PanelMap)

...in the file:

\The Witcher 3 Wild Hunt\bin\config\r4game\legacy\base\input_qwerty.ini

And was all excited, but that didn't change anything helpful. From the main Panels screen, with all the icons for Map, Inventory, Bestiary and the like,Keys like 'I' and 'M' also still work, so I still have no idea where it's getting those keys from. Could simply be the dreaded hard coded.

Find file:
...\The Witcher 3 Wild Hunt\bin\config\r4game\user_config_matrix\pc\input.xml
In section:
<!-- Panels -->
just delete - tags="locked
For example:
="character_panel" displayType="INPUTPC" actions="PanelChar" tags="locked"/>
="character_panel" displayType="INPUTPC" actions="PanelChar"/>
Now You can bind the keys in game menu.
I can't find how to close the map with the same key...

Have you confirmed this as working? I've tried that in the past and it didn't change anything.

The movement inputs are commented out here as well, but de-commenting them doesn't allow them to be remapped from within the game either.