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.
Best Answer
There are multiple ways that this type if flush activator is connected to the lid.
With some you press down hard on the outer ring around the flush knobs and then turn it counter clockwise to remove the button assembly.
Some units may actually require this outer ring to turn around to unscrew from the inner part. Use of rubber gloves can help get a better grip on the ring.
On some others you take out the two buttons (which is often done by pressing one button down far enough so you can get under the other to pop it up) and then inside the opening under the buttons there will be a screw that you remove.
I have read that some others you lift the lid a small way, slide it forward a ways. Then feel along the back edge for a tab that you pull or push to release the lid.
After seeing your pictures I think that you should seriously consider that it may be time to think about how you would ever get this back together if you did manage to get it apart without any broken parts. I'd suggest shutting off the water line at the wall and then just yanking hard to take the lid off. Then retrofit your tank with a newer style mechanism that is built a lot more sane way.
Here are two more modern style mechanisms that could be considered. This first one simply lets the lid freely lift off.
This second style has a short connecting cable that joins the actuator to the flush mechanism so that the lid can be easily lifted up to service the inside of the tank.