Stabilize command does not appear on clip jobs menu version 15.04.3 from https://launchpad.net/~kubuntu-ci/+archive/ubuntu/stable. I am not sure how stabilize gets into kdenlive these days. used to need vid.stab from sunabs ppa. But I can not see this in the kubuntu-ci ppa Reproducible: Always
So I took a kubuntu 15.04 version with fully updated system from the standard ubuntu repositories. And then I added Sunabs ppa offering the 15.04 version - https://launchpad.net/~sunab/+archive/kdenlive-release It has frei0r-plugins ver 1.4-3 from Ubuntu universe and libavformat56 6:11.2-1 ubuntu universe I then installed kdenlive (15.04.2-0ubuntu0-~sunab~vivid4) kdenlive-data (15.04.2-0ubuntu0-~sunab~vivid4) libmlt++3 (0.9.6-0ubuntu0~sunab~vivid1) libmlt-data (0.9.6-0ubuntu0~sunab~vivid1) libmlt6 (0.9.6-0ubuntu0~sunab~vivid1) libvidstab1.0 (2:0.98b-0ubuntu0~sunab~vivid1) melt ( 0.9.6-0ubuntu0~sunab~vivid1) I then obtained a version of kdenlive where stabilize is available. So this is fixed