BoxContainer updates it's actual size inconsistently
Having some experiments with Godot's GUI system, and faced this strange behavior of BoxContainers, for example - HBox and VBox Containers.
When changing Min Size of of their children by code, they change positions of other children properly in whole. But they seem to update their actual size very strangely if the internals became smaller. See this gif:
Here I adjust the min_size of one of the children while dragging the corner (my custon script). The outer red rectangle (ReferenceRect) copies the actual size of outer HBoxContainer. As you can see, it updates it's size inconsistently, one of the results of which is that the right label ("To The Right") is not properly centered vertically.
Is it an intended behavior which I don't yet understand, or it is a bug? Decided to discuss it here first to not "spam" the Issues on Github.