Some letters and characters are printed twice. I type "hello!" and get "hello!". I spend time proofreading and editing. I cleaned between the plastic chains for the switches and helped a little. I bought a phone battery that fit in and soldered wires to it. I have doubled my life. Now I get about 3 days before charging. Everything seems to be fine with the mouse. Flashing lights don't stay on all the time so I can see the buttons. You go up, then down, then up, then down. This aggravates the situation. Also, the 3 backlit colored lights bother my eyes and make the keys difficult to read! The mouse has a switch, thank goodness, to turn off the flashing lights! The screen is important when the game and flashing lights are distracting.