I have a shower stall with one panel that has a window over looking the tub. There is mold on the drywall near where the panel and window and ledge meet. I never see any leaking water from the window or ledge. Do I have to remove the enitre shower surround? I was thinking I could recaulk everything and see if it got worse first? How do I know if there is any water damage that needs repair?

You can't loose much by trying the caulking trick first. Clean everything squeaky clean before caulking. If that doesn't work, bite the bullet and get someone in that you can trust to do the job correctly.

I have a shower stall with one panel that has a window over looking the tub. there is mold on the drywall near where the panel and window and ledge meet. I never see any leaking water from the window or ledge. Do I have to remove the enitre shower surround? I was thinking I could recaulk everything and see if it got worse first? How do I know if there is any water damage that needs repair?
If the panel with the window in it is not the one with the faucet in it, then it is likely just condensation from the shower collecting on the window and running off afterwards. As a general rule, drywall and shower stalls? Bad combo.