There appears to be a fault in the constrained resize algorithm (I admin, by design) which tries to resize the columns considering their max widths when the available space exceeds the sum of preferred widths (ResizeHelper:99).

This causes a weird scenario when a column with large max width (500) set gets resized to be _smaller_ than the rest of the columns, because the remaining columns have the default max width of 5000.

This should not happen: the max width should not affect the distribution of extra space, only to limit the width of the specific column(s).

See attached code example (thanks to Cormac Redmond)