The switches in the presenter (clicker) depicted below normally close when firmly pressed, by giving way and making contact with a positive feeling and sound. However, the bottom-right switch appears to close at a mere touch, so much so that when the switch above it is pressed, the faulty switch also closes. In presentations this is a problem, because when I press page-down (the top-right switch) the presentation disappears (due to the action of the bottom-right switch). Is there a way I can fix the faulty switch? I tried lifting the plastic sheet that covers them, and apparently the metallic tops of the switches are attached to it rather than soldered on the PCB.
Those flexible contacts are supposed to be centered on their places. These are called "tactile membrane switches", by the way.
It seems that metal switch domes were attached carelessly misaligned (shifted down and to the left), but the one in bottom-right corner is shifted more than others. It practically touches middle contact with its top-right "leg".
Peel the tape with domes on it. Clean those golden circles and dots in the middle of them with an alcohol. Align domes properly centered on the circles and it should be OK.
In cheap devices the domes usually held in place with a piece of sticky tape, so if it does not stick back nicely, you can also replace the tape. You can use pretty much any scotch tape or whatever non-conductive sticky tape you have at hand.
The easiest way to do it is put tape upside-down first, then use contact circles as guides for arranging domes on the tape. When everything is in place, flip the tape, do a final alignment and press it down.