Normally, if I select a WiFi network, mi iPad connects to it and not to 3G. Sometimes, however, it does not seem to do so. For example, right now as I write, I am sitting next to my home's WiFi modem, which is readily recognized and shows up in "Settings" as having a strong signal. I keep selecting my WiFi network, the tick or check symbol appears next to it as if the iPad had acknowledged I selected it, but the 3G legend persists in the upper left corner of the screen. This happens from time to time and I don't k ow what to do. It also happened once in an airport at another city It was a source of concern because I didn't want to be charged for roaming, when there was a strong WiFi signal available at the place. Your advice is appreciated.