Does anyone have knowledge about the life expectancy of a Bamboo Fun? I have been using the mouse for awhile now (I switch back and forth between that and the pen) and it has been acting up lately. Takes several clicks to target something, won't drag a layer but "opens" it instead, etc . . . I've had mine for several years now, but can't find FAQ that fit my problem. There is no battery for the mouse so I'm not sure what to try.