...
The biggest issue I've had with WinDev is that it stores pretty much all program code and data in binary format, from queries to window definitions to classes. I don't have any reason not to trust WinDev's editors and storage mechanism; I just like to have the option of viewing source with my own editor, or putting up code on a GitHub repository as I've done with the DevRoadmaps Clarion Library.
I wish WinDev were more open, although clearly this isn't going to be a problem for everyone.
...