Problems in MIDI sound playback

[Franklin0770]

I have a MIDI to USB cable connected to a Yamaha P-140 keyboard and I have the following problem.
When I press a key on my Yamaha keyboard the note is written but I can’t hear it playing. To make Furnace playback the sound, I first have to press a key of my computer keyboard to force the playback and then I can hear my Yamaha keyboard’s key presses. At this point, I’m able to hear the Yamaha keyboard until the sheet loses focus (e.g. clicking on a random window). When the focus is lost, I have to press a button of the computer keyboard again to make sure the Yamaha keyboard is audible once more.
I’m aware this problem should already be fixed, but with Furnace 0.6.3 this happens.

Another thing: the software doesn’t recognise all my keyboard’s bank buttons correctly.