I can't reproduce this with any sample. Have you tried using a different sound driver in the sound setup (f.e. an ASIO driver)? Does this also close the sound buffer? If the "pause" icon in the main toolbar changes into a "play" icon, this is the case. I'm not sure if the video is just badly recorded, but is the play cursor really jumping forwards and backwards during playback?

The jumping is to demonstrate that happens in random parts of the sample (random keys pressed). I'm trying with different audio settings.

Well, it's hard to get this bug, but there is a new discover, you need first open & play some songs and then close all. Next create new IT document (maybe it affect for IT, as I cannot reproduce this with MOD/S3M/XM) and in the first sample load a small sample f.e. a snaredrum, edit & play & undo. Then load the big sample and try sample resampling with it. Combitations of this maybe rebproduce the bug.

I wasn't referring to you jumping around in the sample editor, but in the video it looks like the sample is playing normally, but the playback cursor randomly jumps back by a few pixels while it's playing.

Well, I cannot notice that jumping, but here is the original video recording:

http://www.mediafire.com/?7u7cwij5ehkqsp8

I get this one again in 1.19.03, I'm finding what causes this.

What driver are you using, WaveOut/DirectX/ASIO? Does it also happen with other drivers? If you are using ASIO, does it also happen with the ASIO4All driver?

I get this one at least with DirectX and ASIO (ASIO4All) output. I have not tested with WaveOut.

D'oh... You have "Reset channels on loop" set in the general settings, don't you?

Yes

Well, then it's pretty obvious what happens here and it's not a bug.
You press the play button in the toolbar, which starts playing the (empty) module. As soon as the end of the module is reached, all channels including those that are occupied by the sample or instrument editor are reset (this has to be done because of virtual channel settings etc.).
Solution: Don't hit the play button or simply disable this setting, it's pointless anyway.

Ok, I'll close this bug.

PD: When I compile OpenMPT it runs slowly either in 'debug' and 'release' builds, as seen on the video. Also my compiled exe is bigger than your development build. Why does it happen?

Debug is slow because it's debug. VS2010 generates much bigger EXE files, mostly because of the new MFC version. I dunno if any of the optimization settings are different in the VS2010 project, but that could be one explanation for the lack of speed, or once again the new MFC version could also be an explanation.