- The background (black-point) slider is hidden by default. It is shown from
View > Background slider, or as soon as the background becomes non-zero
(B + wheel), so an active background is never invisible. The choice is kept
in QSettings ("backgroundSlider") and cleared by "Reset all settings".
- Auto contrast, continuous or the one-shot A key, sets the background back
to zero.
- A dataset-info plot without a run colour kept the default QPen: black, and
near-invisible on the dark theme. This is every plot of a live HTTP dataset,
whose run list is empty. It now takes #1F77B4 on the light theme and
#FF7F0E on the dark one (the spots / background colours of the split plot).
Checked headlessly: the rendered line pixels are exactly those colours on
the #FFFFFF and #12142B plot backgrounds.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>