Starting with NMRViewJ 9.0 NMR spectra are generally displayed within Canvas windows as compared to the specialized spectral display windows used in previous versions of NMRViewJ. NMRView has few limits on the user's ability to visualize NMR spectra. As with the number of datasets one can open, there are no arbitrary limits on the number of canvas windows that can be open at once. Likewise they can be displayed with arbitrary locations and sizes on the desktop. Large numbers of canvas windows in arbitrary locations can sometimes be more confusing than useful so NMRViewJ also provides a variety of ways to group related spectra inside a single canvas window. While only one- and two-dimensional displays of spectra are possible, the choice of which dataset dimensions correspond to which display axes is up to the user. Different views, including variations on such parameters as dataset dimensions; plot regions; and contour levels of the same spectrum, can be displayed simultaneously in different display windows. A hallmark of NMRViewJ is the fact that no matter how the spectra are displayed in different windows the positions of the cross hairs in each window are correlated with the positions in every other window in an automatic and intuitive way.