I have just uploaded a beta version of GExperts 1.3.12 for Delphi 10.3 Rio.
NOTE: This is a BETA!
Beware of bugs, e.g. the Goto-Dialog enhancements cause redraw problems if theming is enabled, the Run Parameters dialog enhancements (drag and drop for files and directories) don’t work at all.
https://blog.dummzeuch.de/2018/11/25/gexperts-1-3-12-beta-for-delphi-10-3-rio-available/