I use the mouse to scroll to find the tool is always very slow when using the "Customize Quick Tools" feature. My software version is Acrobat DC Pro 2019.012.20034, and the computer is Mac Pro 2013 ( macOS 10.14.5). My computer configuration is not low, using Acrobat and other software is not slow. Use of "Customize Quick Tools" function is always very slow, it takes a long time to add the required tools on the Toolbar.