SysML nested properties within ports on Parametric diagrams resize themselves!

[fishy]

I have noticed that when I have ports with multiple flow properties or complex structures - e.g. those typed with blocks containing multiple/nested properties (such as SysPhS interfaceBlocks) - the shapes that represent those properties do not always retain their position and dimensions on a Parametric diagram when the diagram is closed and re-opened.
Since it can take a lot of time to lay out a parametric diagram neatly, it's extremely frustrating to close the diagram, re-open it and then find that several things have moved or re-sized!
The underlying issue has something to do with the relative sizes of the shapes and the text they contain.   It appeas that a shape will re-size if the manually set size doesn't allow a sufficient margin around the text.   The same appears to be true of shapes containing other shapes - e.g. a block type containing properties, which itself is contained within a port on the boundary/frame of a parametric diagram:  if there is insufficient margin between a shape and the boundaries of the shapes it contains, then the containing shape may re-size or relocate.

As a supplementary observation, it's really frustrating that the resizing behaviour of ports and the shapes they contain is different:

• the outer boundary of the port shape exhibits horizontal and vertical symmetry.   When you resize it, it's anchored in place by it's centre
• any shapes (flow properties/type blocks) contained within the port do not anchor in the same way, meaning that they have to be manually positioned in the horizontal centre of the port.