Unified margins and spacing in UI tools across OS

[iLLiCiTiT]

Please describe the feature you have in mind and explain what the current shortcomings are?

When layout margins and spacing of Qt layout is not explicitly defined, default OS specific or DCC specific values are used. Which causes bizzare UI layouts with margins and spacing twice as big, leading to huge windows.

How would you imagine the implementation of the feature?

Explicitly set layout margins and spacing on every layout in UI tools.