Panels GridTemplateColumns Property

(Almost) directly specifies the CSS grid-template-columns property. Specified as a vector of vectors rather than a space delimited simple character vector. For example:

   g.GridTemplateColumns←'1fr' '2fr' 'auto' 

If empty (the default), and if AutoSize or AutoSizeColumns is 1, then this property is effectively set to n⍴⊂'auto', where n is the number of columns.

If empty, and AutoSize and AutoSizeColumns are both 0, then this property is based on the proportions implied by the [GridTemplatAreas] property. For example if:

      g.GridTemplateAreas←[ 
                            0 0 0 0
                            1 1 1 2
                            3 3 3 4
                            ]

Then this property is effectively set to

  '3fr' '1fr'

As there are two implied colums, and the first column should take up three quarters of the available space, and the second column should take up one quarter.