You start this window from the main menu "Edit | Search Keywords" (or F3). Different settings are possible for the search of keywords.

Select the desired help system.
Choose different sources for the keyword list (Index).
This option enables the extended <title> tag processing. Keywords from the title of the selected files in your file list are parsed.
<title>KIT Example Title and Keywords</title>
This option enables parsing keywords from the <meta> tag in the <head> section of your HTML file and add them to the keyword list.
<meta name="keywords" content="HTMLHelp, Keyword, HTML, Metadata">
This option enables the extended HTML <a> tag processing. Keywords from the inner text of the <a> tags in the selected files are parsed (e.g. "This is a anchor titled United States").
<a name="USA" id="USA">This is a anchor titled United States</a>
This option enables parsing the anchor ID too. So "USA" is extracted from the HTML code <a .. id="USA"> and added to the keyword list.
<a name="USA" id="USA">This is a anchor titled United States</a>Note: "<a name=" isn't valid in XHTML 1.1. So it's recommended using identical values for both of these attributes to ensure maximum forward and backward compatibiity for browsers.