I have contact widgets for quick dialing and also a weather & time widget. Every so often the widgets do not appear on the home screen, but they are still there (in a way). If I press the empty space where the widget would be, it works - i.e. the contact widget will dial the number if I press the empty spot where it is supposed to appear and the same with the weather widget. Also if I try to set another widget in the "empty" spot, I'll get a message there is no room on the home screen for additional widgets. It's like the widget is hidden so you cannot see it but it still functions.
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