I’m running Linux Mint Mate 19, with the Mint-Y-Dark theme.
Currently installed version of Luminance HDR is 2.5.1 dhor:myway ppa. It seems to run OK, however there are some gui icons missing, as in the attached images below. Nothing major, just on the buttons to add / remove images or import / export tone mapping settings.
Has anyone else experienced this? Or is this an issue with my Mint install? Seems to be the same no matter what theme I use for Mate.