Some third party apps are requiring a complete reinstall in order to work properly with the 4.5 bootleg (I refuse to call it a Beta, since none of us are "testing" anything. We're choosing to load an unofficial OS that was leaked by a carrier.). So far, I don't know of anything that has completely refused to work with the OS. Some isolated incidences of individuals having trouble, but no widespread "this doesn't work" items.
It sounds like with your browser, there is a setting on the 4.5 that needs changing. When you downgrade to 4.2, most likely that setting is pre-loaded for you.
If I knew where I was going, I might already be there. -- Cross Canadian Ragweed.