hi!
i used to use renoise 2.0 for a long time and i recently moved to v.2.8. many improvements and keepin its awesomeness. renoise is a sonic beast! im wondering today if the ability to draw pitch curves had disappeared? i would have used it , but i dont see it anymore, the “sample keyzone” tab replaces it…ok, i could logically do it by using glide fx, but i never managed to succeed with this feature…
Are you talking about the instrument graphic envelopes? They were moved somewhat recently, and can be found under the “instrument settings” > “Samples” tab…you can also enlarge them to full screen now by clicking on the “ext. editor” button.
Envelopes are hidden within the tab when first opening the Instrument Settings tab. Far right hand side of this image, click the little arrow to expand.
Could always have quickly searched the Tutorial/Manual pages 
http://tutorials.renoise.com/wiki/Instrument_Settings