By default, the plot is labeled with the Y-axis as the Run-Number axis. If the scan was made as 2*Theta vs. Temperature, Omega, Chi, Phi, or Translation, and you would like the labeling to reflect that, use the Scan Type menu to select the scan type. (Note: If you select a scan type other than Experiment-Run-Number, and there was no variation in the chosen parameter the plot will be a 2D plot of 2*theta vs. Intensity, and many of the data-points will have been ignored.)