Midi playback becomes muted during recording

[fleesh-bleash]

Hi, I just installed FLStudio 10, and there seems to be something wrong with either me or my midi setup. Here's what happens:

In a nutshell, if I record a pattern in song mode using my midi keyboard, I can not record a second pattern on the same pattern channel/instrument without muting the playback of the previously recorded notes.
Playback afterwards works fine (nothing gets overwritten or anything).
Everything works the way I expect if I don't actually record.

Here is what I can do to reproduce the issue:
Open a new project.
Plug in my midi keyboard via USB. The model is E-Mu Xboard 49.
Open the midi options and enable it as a generic controller.
Switch from pattern mode to song mode.
Select pattern 1.
Record - automation and score.
Play the same note four times.
Select pattern 2.
Record - automation and score.
Play any note on the midi keyboard.
The 4 notes I played before are now muted in the playback even though I can record normally.

If I map a knob to the volume control, it works the way I expect. If I try to record notes, it fails.

Honestly, the playlist window is a little baffling to me now that the (elegantly simple and unambiguous) pattern blocks have been deprecated, so I'm having trouble evaluating if this is a bug/conflict or just user error.

Can anyone tell me where I'm going wrong? This works for me in FLStudio 8 on a different machine.

Win7 64bit.

[fleesh-bleash]

For posterity: it isn't really the MIDI playbac...