Subobject selection - extrusion - history problem

Discovered an interesting phenomenon (bug) when extruding with subobject selection and History recording is enabled. In the file below, there is a surface which has been split with some circles and then all the separate pieces joined back together. The circle curves are hidden. The circular subsurfaces are then selected via subobject selection and extruded with the Gumball extrusion handle.

SO Extrude Problem.3dm (413.7 KB)

If history recording is disabled, things seem to go as expected. However, if history recording is enabled, things go a little crazy - see the video. I suspected that this is because the Ctrl+Shift subobject selection includes not only subsurfaces of a polysurface but also edges and vertices. So that as the original edges get moved during the extrusion, they are re-extruded via history afterwards… uhhh, some of them anyway…

If I turn on the selection filter, activate subobjects and exclude edges and vertices from the selection, then it behaves correctly, which seems to confirm my theory. This is in V7, but I have confirmed that the problem exists in the WIP as well.

Hi Mitch -

On the list as RH-70026 History: Extruding a sub-object face and edge extrudes multiple edges