I have old optical mouse which connects to PC with PS/2 connector. Its left and right clicks are not recognised well. Clicks are recignised sometimes. Left click is rarely recognised. So I removed its top plastic cover, connected to PC, started PC and tried clicking directly on electronics click button soldered on its circuit board. Same behavior. Clicks are not well recognized. However the mouse movement is correctly recognized. So the issue is not that the plastic cover is worn out, right? The issue must have been with the these electronics components responsible to handle click. Am I correct? Am never was electronics student...Is it easily fixable?
[Picture of the mouse attached]