Is there a WYSIWYG GUI editor for this, a la Visual Basic?
Because honestly, you can have the best GUI toolkit in the world but without a visual editor, building a GUI-rich app will still be incredibly tedious.
Tastes clearly differ then, because I've found the opposite. I find visual editor's really difficult to figure out, and I'm much happier when there's a quick to iterate on code-only way of laying out a GUI.
Probably comes from having more experience with web frontends than native GUIs.
GUI visual editors fail when they ignore problems that Borland Delphi and C++ Builder solved brilliantly well over 20 years ago creating an incredibly quick and productive workflow, and yes, they can become an absolute mess because of this.
I can only dream of the day Lazarus (FOSS reimplementation of Delphi) will work with other languages beside Object Pascal.
One problem I usually have with GUI builders is that they generate huge and messy data files for the layout which can't be meaningfully diffed. Visual Basic is even worse because the form files are binary blobs. Lazarus seems to use fairly concise and readable plain-text files for its forms, although there's also some sort of binary resource files.
I think people who prefer and use GUI builders (generally "old-school" native devs) and those who write GUIs in code (generally web devs) design GUIs in different ways.
GUI-as-code makes dynamic layout easier, so those GUIs have more hiding and expanding elements. The GUI-as-data approach leans towards a static UI, disabling the elements that don't make sense right now. Dynamic elements exist only via hand-coded widgets, making GUIs more formulaic.
I may be seeing causality where there is none, though.
Probably comes from having more experience with web frontends than native GUIs.