Go into themes and css and search AdvancedMultiTool and in the css of it find
div[aria-label="(DF42) Advanced Multi-Tool"] .ipsFieldRow_section, .ipsTabs, .ipsTabs_item:not(.ipsTabs_activeItem){
background-color: #4e5b62;
color: white;
font-weight: 400;
font-family: Gill Sans,Gill Sans MT,Calibri,sans-serif;
}
its at the top, Remove it all and it will go, It was supposed to only work in this plugin settings, (like on 4.1) must be changed in 4.2, So just delete that from the css and I will remove it in the next update