Pixel Classification: Added input constraint: all images must have the same number of channels.
DataSelection: Detail table supports double-click for replacing empty rows and editing properties for non-empty rows.
DataSelection: Re-order the layerstack when the user switches tabs so the current role's data is shown on top.
DataSelection: Re-name and emphasize 'add files' button
DataSelection: Support drag-and-drop for adding new input files.
DataSelection:
- Don't save 'axisorder' dataset info field anymore
- use original_axistags (when present) to determine the axis order to show to the user.