Steps to reproduce:
This looks related to T153356: Using browser functions to switch input direction is impossible in the new wikitext editor by @Amire80, but I think it's a separate bug.
This looks related to T153356
Not related.
I confirm this—it does nothing, and the inspector can't even be closed.
It does work correctly when some text is selected. Maybe when no text is selected the Language command should be just grayed-out.
IIRC, @Mooeypoo knows quite a lot about the Language command ;)
Change 330439 had a related patch set uploaded (by DLynch):
ui.AnnotationInspector: Don't assume previousSelection exists
Change 330441 had a related patch set uploaded (by DLynch):
ui.AnnotationInspector: In source mode, provide fallback insertionData
To explain the issue, this is two things happening:
In source mode (NWE), the annotation inspector doesn't have access to the previousSelection property, which it assumes exists when the window closes. This causes the endless-loop of it trying to close, having an error and staying open, etc. Patch 330439 stops that assumption from being made.
When that's fixed, there's still nothing being inserted if you started with a collapsed selection. That's because NWE's annotation method doesn't cope well with empty annotations (they get boiled down to "" in the wikitext-generation). As such, patch 330441 provides a fallback in this case, mirroring the behavior of the italic/etc commands (which generate markup like `''Italic''` in the collapsed selection case).
(The latter patch probably removes all cases where the former is actually required, but I'm not 100% certain of that, so I figure it's better to be safe.)
Change 330439 merged by jenkins-bot:
ui.AnnotationInspector: Don't assume previousSelection exists
Change 330441 merged by jenkins-bot:
ui.AnnotationInspector: In source mode, provide fallback insertionData
Change 332879 had a related patch set uploaded (by Jforrester):
Update VE core submodule to master (6eba2e2)