It would be a nice faeture if assistant would do a fulltext search after remotely searching for a keyword (with "activateKeyword" command) that does not exist. Currently, the "index" string is set (resulting in an empty set for an unknown keyword) but otherwise there is no visual feedback. If the index tab is not active, the user will not notice that something has happened.

Attached is a patch against Qt 4.6.2 which does the following:

• Indoducing a new assistant specific tag in qhcp <assistant></assistant> section named "enableSearchFallback"
• The tag supports the attribute "fieldName" which accepts "DEFAULT", "FUZZY", ... (string representation of enum QHelpSearchQuery::FieldName)
• search fallback is disabled by default, default fieldName is "DEFAULT"
• if fallback is enabled, search tab will be activated if a keyword can not be found and searchEngine is used to search

If a keyword cannot be found and if search does not find anything either, user is now presented with "Your search did not match any documents." Existing tabs showing documentation are not modified.
One little problem exists, though. It does not seem to be possible to modify the text input field in the query widget. At least, previously set query strings should be cleared somehow to avoid confusion.