[bug] MouseEvent.MovementX and MouseEvent.MovementY do not work correctly on Linux

[vim-overlord]

Describe the bug

MouseEvent.MovementX and MouseEvent.MovementY should be equal to the difference between the current mouse position and the mouse position during the previous MouseEvent, but in this case, they seem to be equal to coordinates of the cursor on the page (i.e. the same as pageX and pageY.)

Reproduction

1. Create a project with create-tauri-app using the svelte-ts template
2. Create two files App.svelte and Draggable.svelte with the following contents:

App.svelte:

<script lang="ts">
  import Draggable from "./Draggable.svelte";
</script>

<Draggable>
  <span style="font-size: 8rem;">TEST</span>
</Draggable>

Draggable.svelte:

<script lang="ts">
  export let x = 0;
  export let y = 0;
  let isMoving = false;

  function begin() {
    isMoving = true;
  }

  function end() {
    isMoving = false;
  }

  function move(e) {
    if (isMoving) {
      x += e.movementX;
      y += e.movementY;
    }
  }
</script>

<svelte:window on:mouseup={end} on:mousemove={move} />
<section on:mousedown={begin} style="left: {x}px; top: {y}px;" class="draggable">
  <slot></slot>
</section>

<style>
  .draggable {
    cursor: grab;
    position: absolute;
    user-select: none;
  }
</style>

3. Run the program and attempt to drag the TEST text on the screen

Expected behavior

The text should follow the cursor instead of drifting off the screen

Platform and versions

Environment
› OS: Arch Linux Unknown X64
› Node.js: 18.7.0
› npm: Not installed!
› pnpm: 7.9.4
› yarn: Not installed!
› rustup: Not installed!
› rustc: 1.63.0
› cargo: 1.63.0
› Rust toolchain:

Packages
› @tauri-apps/cli [NPM]: 1.0.5
› @tauri-apps/api [NPM]: 1.0.2
› tauri [RUST]: 1.0.5,
› tauri-build [RUST]: 1.0.4,
› tao [RUST]: 0.12.2,
› wry [RUST]: 0.19.0,

App
› build-type: bundle
› CSP: unset
› distDir: ../dist
› devPath: http://localhost:1420/
› framework: Svelte

Stack trace

No response

Additional context

No response

[amrbashir]

from MDN:

Warning: Browsers use different units for movementX and screenX than what the specification defines. Depending on the browser and operating system, the movementX units may be a physical pixel, a logical pixel, or a CSS pixel.

So it seems that this property is not reliable anyways and you should compute it yourself, MDN also gives you how to compute it properly

currentEvent.movementX = currentEvent.screenX - previousEvent.screenX