The GL2 has a problem where the zoom rocker becomes "sticky" or unresponsive. You can order the part from Canon and install it yourself.
When my zoom rocker started getting bad, I started researching and found that you can send it to Canon and they will fix it for about $250, but you can also order the part for about $20 including shipping and install it yourself. The number for the parts department is 1-732-521-7230. The part number you need is DG1-7395-010. The part costs $13.08 (as of …