There was a configuration issue in RAD Studio Sample GitHub Repository (https://github.com/Embarcadero/RADStudio10.4Demos), namely the fact the demos were configured with LF only (Line Feed), rather CR LF (Carriage Return and Life Feed) as the RAD Studio IDE expects. Compiling and running the demos works as expected, but if you edit them some of the editor helpers will get confused and so the debugger, as the IDE mixes the actual line numbers. This configuration issue in the repository is now resolved. Pulling down the latest demos from our GitHub repo will ensure you get the updates since they are newer than the ones installed with 10.4.
To do so, you can give a Subversion update command (despite being on GitHub, we do interface to the demos via Subversion commands in our installer). Just go to the demos folder (by default something like C:\Users\Public\Documents\Embarcadero\Studio\21.0\Samples) and give an svn update command, or use TortoiseSVN to issues an update, as I did below:
You can see from the download information above that the process was fairly quick.
We recommend checking our GH repository from time to time, to access newly added demos. As you will see in the updated repository, we just included a new 10.4 demo (5 files) in it.