Hey,
I've tried both the version from the official Arch Linux repositories and a self-compiled one, with same results. I had to disable some compiler warnings to build the engine with GCC 8, perhaps that's got something to do with it. When I find the time, I'm gonna try different compiler versions and maybe SDL 1.2 too, and let you know how it went. In case it matters, I play the German version of BG2, installed from original CDs with Wine and with the latest official patch applied. Now I also use the widesceen patch,but the reported behavior also occurs without it.
I've just tried it again with a new party: The key doesn't budge and I get the following message:
[GUIScript]: Cannot move item, it is undroppable!
Ah, I think that's it - only some of the floor traps are resetting while others stay disarmed. In case it still matters, here is the debug dump of one such trap before and after a map change:
[InfoPoint/DEBUG]: Debugdump of Trap Region irenicusroomtrap:
Region Global ID: 11057
Position: 3712.1000
TalkPos: 0.0
UsePoint: 0.0 (on: No)
TrapDetected: 1, Trapped: Yes
Trap detection: 20%, Trap removal: 20%
Script: gtar8, Key: , Dialog:
Deactivated: No
Active: Yes
[InfoPoint/DEBUG]: Debugdump of Trap Region irenicusroomtrap:
Region Global ID: 11347
Position: 3712.1000
TalkPos: 0.0
UsePoint: 0.0 (on: No)
TrapDetected: 1, Trapped: Yes
Trap detection: 20%, Trap removal: 20%
Script: gtar8, Key: , Dialog:
Deactivated: No
Active: Yes
Probably, but perhaps try it in one of the original games. I'm really not sure anymore how they handled this situation.
Right click on an inventory item, then scroll the mouse wheel. Works every time for me. It's weird to describe though. I will see if I can screencap it somehow.