Change 220977 had a related patch set uploaded (by Alex Monk):
VE integration: Provide a drop-down list of available languages

https://gerrit.wikimedia.org/r/220977

Change 232875 had a related patch set uploaded (by Alex Monk):
Allow DropdownInputWidget users to pass configuration options to DropdownWidget

https://gerrit.wikimedia.org/r/232875

Change 232875 merged by jenkins-bot:
DropdownInputWidget: Allow users to pass config options to DropdownWidget

https://gerrit.wikimedia.org/r/232875

Change 220977 merged by jenkins-bot:
VE integration: Provide a combobox for language input

https://gerrit.wikimedia.org/r/220977

With the merged patch, the editor freezes for several seconds when opening the inspector, and it looks all messed up when it does finally open. If I'm not the only person who sees the problem, we mustn't deploy this in the current state.

Looks fine to me (on a Mac), and took about 0.5 seconds to open…

I can reproduce this at http://en.wikipedia.beta.wmflabs.org/wiki/Python?veaction=edit using Firefox or Opera, on Windows 7. Firefox even gives me the "unresponsive script" warning.

Hmm, yes, performance is poor when opening the syntaxhighlight editor on an existing block on a page. Inserting a new one block (even when there's already one existing on the page) is very fast. New task?

Change 234596 had a related patch set uploaded (by Alex Monk):
VE integration: Fix regression in Ic84c5afb

https://gerrit.wikimedia.org/r/234596

Change 234596 merged by jenkins-bot:
VE integration: Fix regression in Ic84c5afb

https://gerrit.wikimedia.org/r/234596

This fixes the performance, but the dropdown still looks completely messed up.

Am I the only person seeing this? If not, why am I the only one caring?

Looks fine to me: