Two findings, both from watching the bar refuse to change.
The Icon widget copies the desktop entry into the user's home and uses
the copy. A classroom that had already run kept the old icon and the old
command for ever: the package no longer contained a bell and the bar kept
showing one. The button is a task manager holding a single launcher now,
which resolves /usr/share/applications live — the place an OTA update
writes to — and costs nothing, because the classroom already runs one for
the applications.
NoDisplay=true then hid the entry from the very index that resolves
launchers, and the bar drew a blank page. There is no application menu in
this classroom for the entry to clutter, so it is indexable now.
Co-Authored-By: Claude Opus 5 <[email protected]>