As soon as the circle touches the referennce images bounds it contiinously shrinks. It shrinks until the center point reaches the image bounds because the other control point is bound by the reference image as well.
|Open||None||T27270 Planar figures are inconsistently bound by reference image|
|Open||None||T27269 PlanarCircle shrinks in size when moved towards image boundaries|
Curently you can workarround by moving the control point (e,g, for size) to the other side, so that it does not hit the boundary.
Should discuss, if we just document the behavior and how to work arround it.
Or if it is realy a bug that should be fixed.
At lease I would lower the priority for now, as we have a work around already.