[nabilt]

If you just want a simple UI editor and don't want to pay for the official tool, give GUI Glider from NXP a try.

https://www.nxp.com/design/design-center/software/developmen...

[Saris]

EEZ Studio is another option that's open source, and I find it a bit easier to use too: https://github.com/eez-open/studio

[echoangle]

Small typo: GUI Guider