Masses briefly stop moving when switching between vertical and horizontal normal modes

[Nancy-Salpepi]

Test device
iPad Air 2

Operating System
15.1

Browser
Safari

Problem description
phetsims/qa#733

I've only seen this on the iPad thus far: The masses will briefly stop moving when switching between horizontal and vertical amplitudes on the Two Dimensions Screen.

Steps to reproduce

1. On the Two Dimensions Screen, increase the Number of Masses to 100
2. Grab a Mass from the middle and move it to one of the edges. Release.
3. Switch back and forth between Vertical and Horizontal radio buttons.

Visuals

particles.temporarily.freeze.mov

Troubleshooting information: !!!!! DO NOT EDIT !!!!! Name: ‪Normal Modes‬ URL: https://phet-dev.colorado.edu/html/normal-modes/1.0.0-rc.1/phet/normal-modes_all_phet.html Version: 1.0.0-rc.1 2021-11-03 19:33:33 UTC Features missing: applicationcache, applicationcache, touch Flags: pixelRatioScaling User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.69 Safari/537.36 Language: en-US Window: 1313x633 Pixel Ratio: 2/1 WebGL: WebGL 1.0 (OpenGL ES 2.0 Chromium) GLSL: WebGL GLSL ES 1.0 (OpenGL ES GLSL ES 1.0 Chromium) Vendor: WebKit (WebKit WebGL) Vertex: attribs: 16 varying: 31 uniform: 1024 Texture: size: 16384 imageUnits: 16 (vertex: 16, combined: 80) Max viewport: 16384x16384 OES_texture_float: true Dependencies JSON: {}

[pixelzoom]

This is not something that will be addressed for the prototype. I'll label it as deferred, so that it can be evaluated for the final public version.

Also not a bug - there is nothing incorrect about the behavior. So I'm removing the "bug" label and adding "performance" label.