Created attachment 466328 [details] missing cut, paste, copy icons in script editor Upstream says no issue in upstream: https://hub.qgis.org/issues/16312 screenshot attached. issue also occurs in 2.18.3-r1 stable
I had obsolete files .qgis2/processing from a previous installation. Clearing out the .qgis2/ folder and restarting solved the issue by qgis copying over the up-to-date files from the latest installation. Perhaps there can be postinstall emerge message to point this out. This can be closed.