Table headers containing spaces are unstable

[Youjin1985]

When I create table with headers, like

header: {
values: [["Averaging"], ["Bulk"], ["Young"], ["Shear"], ["Poisson"]],
}

I find out that its impossible to have spaces in header, like "Averaging Method" - header with space is not shown.
Tried   and it moves text unpredictably.

Its nowhere near production ready, could you please fix such simple and important feature, thanks.