I can think of a solution where the AdaptivePageLayout has a maximumHeaderHeight property that holds the maximum (implicit) height of the header in each of the columns. App developers can then set PageHeader { height: adaptivePageLayout.maximumHeaderHeight } to synchronize the header heights.
However, that means that app developers have to do an effort to synchronize the header heights, and most applications will not have the header heights synchronized between the columns.
I can think of a solution where the AdaptivePageLayout has a maximumHeaderHeight property that holds the maximum (implicit) height of the header in each of the columns. App developers can then set PageHeader { height: adaptivePageLay out.maximumHead erHeight } to synchronize the header heights.
However, that means that app developers have to do an effort to synchronize the header heights, and most applications will not have the header heights synchronized between the columns.