I cannot reproduce this with MNE-Python 1.3.0 with the mne-qt-browser backend on macOS:
# %%
import mne
sample_dir = mne.datasets.sample.data_path()
sample_fname = sample_dir / 'MEG' / 'sample' / 'sample_audvis_raw.fif'
raw = mne.io.read_raw_fif(sample_fname, preload=True)
raw.crop(tmax=60)
with mne.viz.use_browser_backend('qt'):
raw.plot(bgcolor='k', color='w')
produces a figure with black background an white traces.
Regarding the problem with the qt-browser backend when running from Spyder, maybe @marsipu has an idea?
Best wishes,
Richard
