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I have compiled a help project as a CHM help file, but when I enter a keyword on the Search tab, it does not find any topics in the help file despite the topics actually contain text that matches the keyword. So my question is: How do I enable the search function in my CHM file?

I want the users of my Web Help system to have the "Phrase" search option instead of the "Any words" option (on the Search tab) for better search results. Is it possible to select the "Phrase" mode as the default setting?