I've been trying to edit a SpriteKit SKS scene on Xcode 12.3 on macOS Big Sur. I can add sprites, move things around, etc. - but some completely normal things cause Xcode to misbehave or crash entirely for me:
Undoing changes with Cmd+Z can sometimes cause a crash such as this - this happens almost at random for various changes to a scene, rather than in a manner I can reproduce:
Code Block DVTUndoManager for delegate:<SKSceneDocument 0x7fb483740220> Sending undo: to IDEInspectorViewController from <NSMenuItem: 0x7fb480f5ce70 Undo> ProductBuildVersion: 12C33 UNCAUGHT EXCEPTION (NSInternalInconsistencyException): undo: DVTUndoManager 0x7fb48480a770 is in invalid state, undo was called with too many nested undo groups
I can't edit actions / animations from the timeline for some nodes, but I can for others. Adding, for example, a "Move To" action to any node with child nodes beneath it, clicking on the action in the timeline entirely blanks out the right panel instead of letting me edit the properties of the action. Trying to make changes to actions often causes things to crash as well.