Hi, I'm having similar problems. If I open the app by double-clicking it, it has some sort of memory leak. I can watch as my available memory goes from 1.30-ish GB down to 25MB over about 20 seconds, at which point the app crashes and my system shudders. During these 20 seconds I don't get the chance to do anything, just boot/leak/crash.

This is an image sequence showing the memory leak happening.
However, if I launch the executable using the terminal (from within the actual app package, eg. ** ~/Applications/WavePad.app/Contents/MacOS/WavePad **) it runs fine.
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Let me add a second to those wanting a stop hotkey (space).
Also, I tend to have to click the 'stop' button a few times (even when the file hasn't been played yet) to un-grey all the options in the menus, like effects and processes. Otherwise nothing is available to do.
And half the time there is no Undo option.
Also, I can't paste without selecting some audio to paste-to first. How is that useful? I want to paste at a point, not over other data.
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This program definitely looks like something I'd like to use, but it's FAILing massively at the minute. Frankly, Audacity has it's own quirks and glitches that annoy me and I'd switch for anything else in a heart beat (I still haven't found anything on a Mac as good as SoundEdit16, back in OS9 - clean/simple/useful), and your program looks like something I want to use.
Please help me kick Audacity!