Using i2c/eeprom_24xx/microchip_24lc64/sainsmart_dds120_powerup_scl_sda_analog.sr as an example.
Issue #1: When zooming in on the "flat" part in the beginning, the smooth trace becomes slightly grainy. Painting is done via AnalogSignal::paint_envelope().
Issue #2: When zooming in further, the trace becomes thinner. Painting is done via AnalogSignal::paint_envelope().
Issue #3: Zooming in even further, AnalogSignal::paint_trace() takes over and the trace is suddenly too thin to even see. It becomes one with the zero line, giving the impression that the trace isn't even drawn. Zooming further in shows however that there is a trace once the sample dots become visible.
As those issues are very likely related, I'm only creating one bugzilla entry.