Context

Discord discussion https://discord.com/channels/1195771303215513671/1195779663386136706/1361366213774802974

It appears children of ScreenElement do not inherit their parent's local space. They get assigned a CoordPlane of Screen which then I believe causes this to reset the position back to the contentArea

Proposal

The only options for CoordPlane are World and Screen, where Screen apparently doesn't translate from the parent if the entity is a child. I think it would be more clear to have an additional CoordPlane.Local which is the default for any child, and would act appropriately based on whatever CoordPlane the parent has.