Produce a kFixed input widget based on the size classes.
kFixedWidget(sizeclasses)kFixedWidgetHeader(sizeclasses)
kFixedWidgetRow(sizeclasses, sci)
Vector of size class names (from the reactive values list).
name of size class element index.
Rendered HTML kFixed input widget.
kFixedWidgetHeader creates the widget header based on
the number of size classes.
kFixedWidgetRow creates a row of the widget (input
for one size class).