Looking at the User-Agent string sent to WebKit, the first [few] time uses the default string before the user defined
string is used. Check this log of these calls:
midori_web_settings_set_property.1656 - user-agent = 'Mozilla/5.0 (Macintosh; U; Intel Mac OS X; c) AppleWebKit/535+ (KHTML, like Gecko) Version/5.0 Safari/535.10+ Midori/0.4'
midori_web_settings_set_property.1648 - user-agent = 'Mozilla/5.0 (Macintosh; U; Intel Mac OS X; c) AppleWebKit/535+ (KHTML, like Gecko) Version/5.0 Safari/535.10+ Midori/0.4'
midori_web_settings_set_property.1656 - user-agent = 'Mozilla/5.0 (Macintosh; U; Intel Mac OS X; c) AppleWebKit/535+ (KHTML, like Gecko) Version/5.0 Safari/535.10+ Midori/0.4'
midori_web_settings_set_property.1656 - user-agent = 'Mozilla/5.0 (MyPlatform; Macintosh; U; Intel Mac OS X; c) AppleWebKit/535+ (KHTML, like Gecko) Version/5.0 Safari/535.10+ Midori/0.4'
midori_web_settings_set_property.1656 - user-agent = 'Mozilla/5.0 (Macintosh; U; Intel Mac OS X; c) AppleWebKit/535+ (KHTML, like Gecko) Version/5.0 Safari/535.10+ Midori/0.4'
midori_web_settings_set_property.1648 - user-agent = 'Mozilla/5.0 (Macintosh; U; Intel Mac OS X; c) AppleWebKit/535+ (KHTML, like Gecko) Version/5.0 Safari/535.10+ Midori/0.4'
midori_web_settings_set_property.1656 - user-agent = 'Mozilla/5.0 (Macintosh; U; Intel Mac OS X; c) AppleWebKit/535+ (KHTML, like Gecko) Version/5.0 Safari/535.10+ Midori/0.4'
It also seems that sometimes the user supplied string is even forgotten (above, after sending the special string once, it reverts back to the default)
