title: Is it possible to drag & drop between custom VS Code tree views?
body: <p>The 1.66 (March 2022) release introduces a <a href="https://code.visualstudio.com/api/references/vscode-api#TreeDragAndDropController%3CT%3E" rel="nofollow noreferrer">TreeDragAndDropController</a> API which allows for handling drag &amp; drop events for custom tree views.</p>
  <p>However in the docs for the <a href="https://github.com/microsoft/vscode/blob/dc2f5d8dd1790ac4fc6054e11b44e36884caa4be/src/vscode-dts/vscode.d.ts#L9783-L9786" rel="nofollow noreferrer">DataTransfer</a> object is says:</p>
  <blockquote>
  <p>Drag and drop controllers that implement {@link TreeDragAndDropController.handleDrag <code>handleDrag</code>} can add additional mime types to the data transfer. These additional mime types will only be included in the <code>handleDrop</code> when the the drag was initiated from an element in the same drag and drop controller.</p>
  </blockquote>
  <p>Does this mean that you cannot drag &amp; drop between custom tree views as they would typically have a custom drag &amp; drop controller per view? Or that you're meant to re-use a drag &amp; drop controller between tree views in order to enable dragging &amp; dropping between views?</p>
  <p>I have tried various combinations and been unsuccessful in getting a full drag &amp; drop between two tree views. I do see an error in the console on drop in some situations but that is about it.</p>