Oh the VBX > OCX transition nightmare...

At the time I worked for an organization which pretty much had an unlimited budget for development and had therefore purchased just about every VBX bundle. They also had a solution with about 90+ complex forms - and no standards, so each developer of each form would pick whichever VBX control that "pleased their eyes". Which was "fine", until about 50% of those VBX control vendors simply did not offer an OCX upgrade in a timely manner - or in many cases simply folded/stopped entirely...

(The next nightmare was transitioning to what was supposed to be a more loosely-coupled COM type architecture, where each form could be dynamically loaded - except, referenced dependency tree and "breaking-binary-compatibility" during weekly "clean builds" ended-up taking sooooo much time... Thanks to a tool from a MSFT employee via their consulting service called "VBBuilder" (think of essentially "make") finally helped reduce that manual effort from a full day to just minutes...)