gui_toolkit 0.56.2

Fixed

• examples/whatsnew no longer stretches while it is resized: a composition swap chain with a fixed surface, as opencode native, and inner = true for the frames of a live resize. The other examples keep the ordinary swap chain, which stretches.
• A lazy column's height changed at every frame when an item showed nothing: its height of 0 counted as not known yet, so it stood for the mean of the others as a space and for nothing when built. A scroll box following its bottom had its scroll bar jump, without end.