This seemed to be working OK in 3.0.6 when I just tried adding markers.
I seemed to be able to put red and green round all the edges same as before
Thanks. Sended the project to Thomas for testing.
I loaded the project on a different machine that still runs 3.0.5. the two red markers are very close to the edge.
The machine has the same GPU but different CPU.
On my normal workstation that runs APG 3.0.6 the problem is there when using the GPU. When I turn off the GPU option the problem is not there!
GPU in compatibility mode the problem is there.
So it has to do with the GPU-routines of 3.0.6.
Now curious to see what Thomas is finding.