Row cell strecth

I’m trying to make a row with 3 equally high cells, something like the last example in this link:

Page Builder Cell Vertical Alignment

I want each cell to have different background colors. If i on the row sets “Cell vertical alignment” to “stretch” i can see that the _cell_ has the right height (using the chrome inspector).

So. If i in each cell add a SiteOrigin Editor and sets this background color to red, blue and green, the background colors do not strecth. This is logical and ok.

So, then i remove the colors for the widgets, and for each cell set the background colors as above. This is when it gets weird. Each cell gets the right color, but they also get 100% in height. That is the current viewport height. The height is no longer the height of the highest widget – it’s now 100%.

What am i doing wrong? Or better – how can i achieve 3 equally high widgets (with background color) without fiddling with margins and paddings for each widget?