Impr sugg: wave editor: keeping left mouse button pressed outside of waveform panel should continue drawing

[GoogleCodeExporter]

When you keep the left mouse button (LMB) pressed during drawing and you go 
outside of the waveform panel, it now doesn't do anything. IMO it should draw 
the max value for the X-coordinate you are on. Drawing a piece of the waveform 
on max or min values is now almost impossible.

Original issue reported on code.google.com by [email protected] on 17 Aug 2014 at 2:31