I noticed that on the scaling - it took a bit getting used to, but I imagine the scaling you made is a handy feature when you want to make a template for midi controllers that don't support value ranges.
I already thought it might change so I made the slider table in such a way that I can easily change the parameter range calculation.
These changes are ofcourse a bit dodgy when you make an editor for HAWK. I hope the rest of the implementation will not change that much.
The Jazz-plugin is quite new on the linux platform indeed so I can imagine that might give some glitches. it would be great if browsers would support MIDI straight from W3C specs, but at the moment this MIDI definition (chrome canary has it I believe) is even more beta than my editor...