Window shrinking and scrolling back to the top in GMail for iPhone are done using JavaScript. So to fix this we need to have some way to modify a part of original JavaScript code. In MicroB Greasemonkey is used for this purpose. As for Tear, I currently don't know about any way how to change source code of a webpage on client-side or inject user-defined JavaScript code into it. Tear has a nice property for modifying css on client-side - "user_stylesheet_uri". If there was a similar thing for user-defined javascript (like "user_script_uri"), then we could add a user-defined scripts and execute them (and hopefully fix the GMail). This is just an idea, I don't know if it is implementable.