Impossible drag and drop from stash

[inbadreams]

Hello there,

After 40 hours without any problem with the game, I met one with the stash of my characters.
I'm in the Dyrford ruins, easy mode, just before opening the blood pool doors.
I found the key for the doors but I cannot drag and drop it from stash to inventory and that's why I cannot open the doors. All quest objects and ingredients are stuck ; only right click works (description).
I realised main character inventory was full when I found the key, then it has been stocked in stash, so I tried to make room in all characters inventory but it didnt work.
I uninstalled the game (from Steam, so only main files) and reinstalled it but the problem is still on. Tried to reboot Steam then Windows, first. Files integrity is OK.

I tried very old saves and it's the same : ingredients stuck into stash (no quest objects in old saves).
Unfortunately, I cannot remember a time when I dragged and dropped ingredients or quest objects, maybe the problem exists since the very beginnig...

Any clue ?