Issues with cursor positioning and scroll behavior during dispatch

[devleejb]

Describe the issue

I'm developing the collaborative markdown editor with codemirror.

video.mp4

However, there are following issues.

1. While dragging with the mouse and executing the following code, the starting point of the drag moves to the topmost position. (Dragging with the keyboard arrow keys works fine.)
2. If the following code is executed during text input, there are intermittent instances where the scroll jumps to the top and then returns to the current position.

view.dispatch({
    changes: { from: 0, to: view.state.doc.length, insert: text.toString() },
    annotations: [Transaction.remote.of(true)],
    selection: {
        anchor: ...,
        head: ...,
    }
});

Browser and platform

Chrome, macOS (But, maybe all browsers and platforms)

Reproduction link

https://github.com/devleejb/codemirror-dispatch-test

[marijnh]

If you replace the entire document, that will reset the editor's scroll position. In most cases, you really want to make the most minimal change possible, rather than a full reset like that. It sounds like you're not actually loading a new document, if you expect the old cursor/scroll position to still make sense, but only modifying the current document.

[devleejb]

In most cases, I apply only the minimal changes possible. However, due to network delays, there are times when the entire document is replaced. At those moments, I also update the cursor position using the selection field. Is it expected behavior that the cursor still moves to the very top, even when the selection field is provided?

[marijnh]

The selection field sets the cursor, so no, that shouldn't be moving to the top. The document scroll position, though, will move, if all content is deleted and re-inserted.

[devleejb]

But, it seems that there are instances where the scroll jumps to the top and then returns to the current position.