I can reproduce what you see when I use a larger texture. I also notice that the Console output is odd. lots of empty lines and a strange order of the lines.
I'm not sure what it is yet.
so as a consequence, there is no chance to set a own adress for the home-button? To create it as a part of html isnt possible in my case .. its a portal which references to a lot of differet homepages and i can't change them .. and a test with own buttons and an iframe destroyed the possibility to get information from the website to sketchup...