Why are page breaks not allowed within containers?

[Flightkick]

Stumbling across #934, I wonder, why are page breaks not allowed within containers?

[PgBiel]

I believe page break is an element by itself (when considering internal code), so, from my current understanding (which might not be fully accurate), it has to be a direct child of the outer page element to be recognized as such.

[laurmaedje]

For some containers it simply doesn't make sense to have a break in them (e.g. a box in a paragraph). For others, e.g. columns, it could make sense and is more of a current limitation that it's not possible.

[KronosTheLate]

The following worked for me. I have included some comments and stuff not used to help people come up with better alternatives. Ideally one that does not require passing in the number of columns.

#let my_pagebreak(n_cols: 2, ) = [
  #context[
    // #let n_cols = page.columns  // I wrap thing inside a #columns function to allow breaking out as needed. page.columns does therefore not do the job for me.
    #let width_page = page.width
    #let width_col = width_page/n_cols
    #let x_init = here().position().x
    #let n_current_col = calc.ceil(x_init/width_col)
    #let n_colbreaks_required = n_cols - n_current_col + 1
    #text(1pt, luma(100%))[#n_colbreaks_required] // The function breaks without this. Seems like an anchor for the colbreaks somehow
    #for _ in range(n_colbreaks_required){
        colbreak()
        // text[I am at page #{here().page()}]  // This reports the wrong page...
    }
  ]
]