How does one combine 2 inventory items?

[GT90]

I'm early in the game, in possession of a letter opener and a sealed envelope. Logically, I'd say the former should fix the latter handily. However, I can find no method of using the opener on the envelope - I can activate either one item, but not both to interact. What's the trick here?

[GT90]

Sorry, just figured it out. You may ignore this thread!

[telamiina]

What was it? Same problem :D

[GalacticGuerilla]

What was the solution!? Maybe it is because its late... but i have to say i am amazed how they made such a straight forward task in such a headache.... So immersive.

[chianeko]

I was stuck in the same place, but found a solution! In the inventory screen, click on the brain, then add the two items to the square on the ride side and click on the gears. If it doesn't work, you might need to fiddle around with the list side until a hint pops up.

[Munty]

Originally posted by chianeko:

I was stuck in the same place, but found a solution! In the inventory screen, click on the brain, then add the two items to the square on the ride side and click on the gears. If it doesn't work, you might need to fiddle around with the list side until a hint pops up.

Playing this game for the first time NINE YEARS LATER and this still had me stumped! The most unintuitive piece of UI I have ever seen in my life!