What is your Obsidian installer version, as well? If it’s an older installer, you might want to try downloading the latest installer from the Obsidian website. There are some components of the editor which cannot auto-update.
Have you tested this in the Help Vault, or by turning off community plugins in your own vault?
@rigmarole So sorry. I celebrated too early. But I found the exact steps to reproduce the bug.
Started Obsidian v0.13.12 (v0.12.19 installer version) with nothing but Excalidraw loaded. (Default theme and no extra CSS snippets)
Opened a regular Obsidian note. Drag and drop work perfectly fine.
Then, when I open an Excalidraw drawing, drag and drop stops working for regular Obsidian notes.
I wonder if this bug is triggered by Obsidian or Excalidraw or both? If it is coming from Excalidraw, would you please tell me how I shall go about reaching out to the Excalidraw dev?