Water is contantly leaking so I want to open the lid of the tank and fix the leak. However, I can't open up the lid! Any ideas?
Picture 1: The water tank from above. The two buttons lifted out from their places.
Picture 2: The lid pushed up as high as possible. A vertical plastic cylinder seems to be under the buttons.
Update after the comment of Wayfaring Stranger.
Picture 3: the lid lifted up as much as possible and slid aside as much as possible. The plastic structure under the buttons keeps the lid near its central position.
Update after the answer from Michael Karas.
Sqeezing in a compact camera on the left then on the right (at the cost of some crepitating noise) I managed to make Picture 4 and 5 of the inside.