/plotman.py
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- Review canvas.update_figure - is this appropriate?
- Replacement for MPL Tk Viewer (?)
- Colormap hierarchy
- Colormap names (?)
- Implement contour plotting / overlays
- Connect to VSO and other data services
- Disambiguate plots with identical names, numerical suffix (?)
- Dynamic subplot adding
- Overlaying plots, drag-drop, opacity etc.
- Handle exceptions ?
- Displaying mapcube animations
- Is gui.ui necessary?

/mainwindow/widgets/figure_canvas.py (?)
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- data xy plots
- ut plots (time series)
- image plots
- spectrogram plots

/mainwindow/widgets/tab_page.py
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- Let Qt Designer do the work.
