Hi Assam, in version 2.11 overlay blend mode Multiply works different than in version 2.10, i assume in 2.10 it was correct.
I used satelite as base and osm vector as overlay.
White areas in Multiply were transparent, but are no longer.
I downgraded to 2.10 and immediately saw it fixed.
Please use automated tests, thank you in advance if you fix it.
hello. sorry for this. problem already reported and solved, more here https://getsatisfaction.com/locus/topic ... aps_broken (https://getsatisfaction.com/locus/topics/overlayign_altitude_contours_using_vector_maps_broken)