For example, draw a rectangle, duplicate it (not in place, but overlapping), select both and do make them union. The upper left corner is visibly 'clipped'.

This is caused by the conversion to path and the upper left corner happens to be the placement of the first and last points. This becomes most visible if the line has a thick stroke. Moreover, neither the origin nor the end point of the path are selectable as points (at least, I was unable to select them by clicking).

This can be worked around by selecting another point and using the edit palette to go to prev/next point, moving the point, closing the path and deleting the extraneous point.

This was only tested with the box tool

------- Additional Comment #1 From Tim Doty 2005-12-29 03:55 -------

This bug is still present in PgS 5.0.2.10rc3 with the proviso that the points can be selected normally. Issuing CLOSEPATH closes the path, but leaves all points intact so there is an extra point in the path.

Tim Doty 2005-12-29 02:28

Actually tested with PgS 5.0.2.10rc3

Draw a path with the pen tool, closing it by clicking on the final point.
Draw a second path inside the first, likewise closing it.
Select both paths and choose Object/Path/Subtract

Each path will have been broken and an extra point inserted so it is not immediately apparent. Move points until the break is found.

Draw a box. Draw another box inside it. Select both and /Object/Path/Subtract. The upper left corner will be replaced by two non-joined points for each subpath.