Style Editor shows original source loading error with iOS 9.2

[jryans]

If "Show original sources" is enabled, I get:

valence:>>>>>> Received from toolbox
{"type":"getOriginalSources","to":"chromium4.chromium_stylesheet24"} server.js:42
Error: Method getOriginalSources on actor chromium_stylesheet is not yet implemented
Stack trace:
exports.todoMethod/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://fxdevtools-adapters-at-mozilla-dot-org/lib/util/protocol-extra.js:14:11
actorProto/</handler@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/server/protocol.js:1013:19
Connection<.onPacket<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://fxdevtools-adapters-at-mozilla-dot-org/lib/chromium/server.js:55:7
TaskImpl_run@resource://gre/modules/Task.jsm:319:40
TaskImpl@resource://gre/modules/Task.jsm:280:3
createAsyncFunction/asyncFunction@resource://gre/modules/Task.jsm:254:14
LocalDebuggerTransport.prototype.send/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/transport/transport.js:569:11
exports.makeInfallible/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/ThreadSafeDevToolsUtils.js:101:14
exports.makeInfallible/<@resource://gre/modules/commonjs/toolkit/loader.js -> resource://devtools/shared/ThreadSafeDevToolsUtils.js:101:14

and a "Style sheet could not be loaded" error appears above the toolbox. Clicking on the sources listed and editing them does seem to work, however.