nooverlap: zero-sized rectangles overlap contrary to what documentation says

[yurivict]

Describe the bug
The documentation says about nooverlap:

Note that the width or the height of a rectangle can be zero. In this case, the rectangle
does not occupy any space. However no other rectangle is allowed to be placed where the
zero-sized rectangle is placed.

However, rectangles from the solution do intersect.

To Reproduce
This program:
testcase-nooverlap.cpp.txt
returns solutions that have all zero coordinates (all rectangles intersect).

Gecode and Platform Configuration
Version: 6.3.0 (0916a1a)
OS: FreeBSD 13

[zayenz]

Interesting discrepancy. There are apparently no tests with boxes with zero-dimensions, so it is not unexpected that this might be a problem. I also think I know how this might happen, but unsure on how to best handle it.