Gradient wrong after merge paths with gradients

[David Mathog]

If there are two or more paths precisely butted up against each other, each with its own linear gradient, then when path->union is applied the resulting gradient is not the union of those gradients, but just one of the gradients. In the attached case there are 3 rectangles each with its own 2 stop linear gradient. All of the gradients are perfectly lined up - the end points fall in a line, and each pair of objects has one overlapping endpoint that has the same color.

In this example (for instance):

1. Select the top rectangle (blue to yellow gradient) and the middle rectangle (yellow to black gradient).
2. Path->Union

Result:

Combined path is the combination of the two rectangles. (This is correct)
Gradient is the one from the original top rectangle. (Maybe correct, not ideal.)

Preferred result:

Same path, but the gradient would have all 3 stops: Blue, Yellow, Black, and would extend over the new object.

I understand that the general cases for merging linear gradients are complex. It is far from obvious what the right action is if the gradients are disjoint, or not aligned. However, if the input is "nice" with the gradients perfectly lined up and abutted, as here, it would be nice if Inkscape would do the right thing and make the expected 3 stop linear gradient.