Buttons still sensitive after clicking "continue" on "updates and other software" page

[Nathan Teodosio]

1. Go to "updates and other software page" (where you can choose normal/minimal install, third-party stuff etc.).

2. Click continue.
   The button becomes insensitive and the cursor becomes a spinning circle.

3. Before Ubiquity advances to the next page, click the minimal installation or any of the check-boxes.

Expected: The buttons ignore the mouse clicks, since continue was already clicked and work has already started in background.

Observed: The buttons will change according to the mouse clicks. This leaves one wondering which settings will be taken into account: The last one he selected or the ones before he clicked continue — it seems to be the former, since I see various removals (hunspell-*, libreoffice-{help,l10n}-*, thunderbird-locale-*, cryptsetup, dbus-x11, ...) in the final phase, indicating a minimal install.