reproducible on Arch Linux (plasma 5.12 beta) and neon dev unstable open system tray settings under "extra items" check "weather forecast" and apply right click "weather forecast" icon in system tray and open its settings "Show temperature in compact mode" checkbox is disabled in "appearance" section
Thanks for the report. Though the setting is disabled on purpose, as entries in the system tray have to be square, and the current layouting code of the weather applet has no support for ensuring that, so for the system tray it just uses the weather state icon, which is square. Writing such code will be some more effort (to me), so no immediate plans for that myself. For now though it would be good to have the user know the reason why that setting is disabled, that should be obviously added. Will ask the VDG how to do that. If you have some proposal what you would expect to see as notification or can point to solutions for similar cases, please tell me here, so the solution can be made to follow existing patterns.
Thank you Friedrich. Unfortunately I have no idea to improve the usability.
Friedrich, could you clarify if further information is needed? If you need input from the VDG, you could point them here. I think we have a bugzilla flag to request feedback from the VDG or usability team.