The x-axis on the 1D display is shifted by 0.000624 ppm relative to the spectral data it's plotting (when using data located in internal/data/1dMetsSpectra). This is not the case when plotting arbitrary curves using pyqtgraph ( strip.plotWidget.addItem(pyqtgraph.PlotCurveItem(x,y) ).
I know this seems like a small amount, but is quite disconcerting when fitting 1D peaks.
The (API DataSource) function get1dSpectrumData() had the spectral width going from point 1 to point n (n = number of points) rather than n+1. Now fixed.