id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
22	Don't redraw full scene to update measuring line	Olly Betts	Olly Betts	"When the measuring line needs to be drawn/redrawn/undrawn, we currently redraw the whole scene each time.

Perhaps we should save the existing image (or the part of it under the line) and restore that instead.  Particularly for slower OpenGL implementations, this is likely to give a much more responsive feel.

(""Son of #17"")"	enhancement	assigned	minor		aven	1.1.16