This indeed restores previous behaviour (or a similar behaviour), but prevents displaying the label and statusbar for the case BLOCK_SOURCE_NONE. I intended to display e.g. ``No block source available...`` with progressbar showing ``x days behind`` for that case. IMHO we should try to find what is causing the bug instead of just preventing it :).

That said I would consider this as work-around hotfix but not as fix for the real problem that causes #2643. But perhaps you are able to debug further? Can you tell if clientModel is set for you when the bug occurs?