Here you can see it happening with the Yeast Alcohol Tolerance function.
The calculator seems to be composed of three blocks, the first being "Batch data", the second "kg Grain", and the third the part were you read the results. These blocks appear to be embedded in the greater field that constitutes the totality of the calculator. The problem then seems to be that the blocks do not float on top of the greater field, but rather are immersed in it. Thus, when a menu is activated and hits the boundary between the block and the greater field, the menu disappears behind the greater field.
I don't know if that's a helpful description. I'm totally ignorant about programming, so I'm just trying to tell what it looks like.
edit: I just tried using another browser (Edge) and that didn't help
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