low resolution icons in menu in libreoffice

on my Laptop=Dell latitude E6510, RAM=8Gb, GPU=GT218 NVS 3100M, CPU=i7 Q 720 @ 1.60GHz running opensuse leap 42.2, plasma 5.10.3, KDE frameworks 5.36.0, KDE applications 17.04.2, Kernel 4.4.74-18.20-default, nvidia drivers, libreoffice
after upgrade to libreoffice I found menu icons ugly and pixeled (I intend that you can see the square pixel forming the icon) due I suppose by low resolution. I use (options>view) oxygen icons but I tried also tango and breeze, how can I have the better icons like in the past??