Problem editing blines, dynamic vertices, and activepoints

Hi Guys,

While playing around with the flower animation tutorial, I came across the following
problem in synfig studio. For ease of explanation, I simplified it into the following
example. Consider a 6-second animation of a square of which the right side moves
inward and back.

What I did was the following:

  • Make animation 6 seconds long
  • Create a white background
  • Create a red square using a filled bline region (no outline)
  • Create a keyframe at 1 second
  • Create a keyframe at 3 second
  • Create a dynamic vertex on the right side at 2 second
  • Move the dynamic vertex inward

The following is as expected:

  • The animation works as expected.
  • The dynamic vertex influences the right side from 1 second to 3 seconds.

The following is not as expected:

  • At 1.5 seconds, eventhough the region is curved inward, the editing line
    (where you can, for instance, add new vertices) is straight vertical.
  • Only at exactly 2 seconds are the ducks of the dynamic vertex visible,
    nowhere else between 1 second and 3 seconds (what I would expect).
  • Duplicating at 2.5 seconds the waypoint of the dynamic vertex at 2 seconds,
    doesn’t result in showing the ducks of the dynamic vertex at 2.5 seconds.

It seems to me that these last three points are bugs. Is this correct?
I have attached the example file. If so, I’ll add an issue to the bugtracker.

dynvert.sifz (1.12 KB)