Charles Schwab lost a big court decision last week in a case that has significance for investors in mutual funds. A federal judge ruled that Schwab violated the law when its YieldPlus (SWYSX) ultra-short bond fund failed to get shareholder approval before loading up on mortgage-backed securities. When the market for those securities collapsed, the fund lost 36% — a nasty surprise for investors who believed that YieldPlus was a safe alternative to cash. Left to decide is the amount of damages the investors should receive; lawyers say California investors alone lost about $170 million, the rest about $800 million....