I know 4.5 is not ready yet so things may change, but in anticipation of 4.5 I tried my project in the latest build of the engine (9/18/2014).
I found that my UMG interfaces I had made in 4.4 are all broke, as buttons now have their own OnClicked events rather than being bound to functions. So clicking them does nothing.
Is this expected - that there will be no backwards compatibility between UMG in 4.4 and 4.5 in that regard?
It’s expected, we attempted to maintain backwards compatibility when possible, but because it’s experimental we broke backwards compatibility when needed - this was one of those few cases.
Cheers,
Nick
Hi, please answer my question and reportbug using UE4.5 version, 3 days no one answer 
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Same thing here just copying all the nodes from those functions that were bounded before in 4.4 and just attaching them to the new 4.5 OnClicked events. Works fine now