Directory Opus 13 showed a delay of about 10 seconds duration when responding to right-click context menu invocations, while right-clicking the same item in Windows Explorer showed no noticeable delay.
Following the instructions in the Crash, exit or high CPU when right-clicking certain files FAQ thread, I received a message in DebugView containing the reference /apps/drive/cello/util/blocking_queue.h:160.
Although the message gave no indication of the culprit for its existence, I intuitively performed an uninstall/reboot/reinstall cycle for Google Drive for Desktop.
This helped and fixed the issue.
I am occupying this thread because it appeared in search engines when I encountered the problem, just in case someone else experiences the same issue and tries to look up the message they get. There are currently no search engine entries indicating that DebugView messages containing a reference to /apps/drive/cello appear to be coming from Google Drive for Desktop (Windows).