The selection tool is probably the weakest point of Pixelorama right now, and we plan to improve it and add more selection tools in a future update. As for the bug, we cannot replicate it. However, the timeline has changed a lot in v0.7 so it's possible it may have fixed itself. v0.7 should release very, very soon!
cool also i want to add a suggestion
the ability to edit more than one layer
some times you want the work to effect more than one layer
i really want to participate in this software unfortunately i don't know anything about godot or gdscript