One situation that stuck in my mind was when i used a separate program (Qt Designer) to create some UI for a custom panel in the editor and was writing both code to make the editor see the panel and wiring event handlers by hand, all the time feeling miserable thinking how Lazarus would do that for me without even needing to write any code so i could focus on the actual feature instead. Qt Designer feeling alpha software at best (it was buggy and otherwise trivial things like moving some controls to a new empty parents was hard to do - in comparison even wxFormDesigner, which i had used at a previous job where the engine there used wxWidgets, would allow you to do by drag-and-dropping and even scaled up the containers to make them easier to target).
I never used C++ Builder professionally but i do have a copy i bought off ebay some years ago and played around with it making a simple 3D mesh editor[0] and dungeon editor[1], among other things. I do wish i could use VCL in C++ projects, but i'd never recommend it these days considering how Delphi is treated by Embarcadero (stupidly high prices), let alone C++ Builder that always felt like a second class citizen - and TBH i'm not very keen on recommending a proprietary framework anyway.
I've long decided that the best you can get with C++ these days is Qt Creator.