Call Milgard before you mess with it. If it has a warranty and you have done anything to remove it, you may have voided the warranty. And yes, any of the panes can be replaced.
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Due to a minor mishap, I now have 15# balls. . . ...

Decisions are made by those who show up.

"Shallow men believe in luck. Strong men believe in cause and effect." Ralph Waldo Emerson