Cut off dots on wave examiner

[KatieWoe]

Test device:
Dell Laptop
Operating System:
Win 10
Browser:
firefox (not seen in chrome or edge)
Problem description:
For phetsims/qa#238. May be related to #235 but it isn't fixed in master.
The dark and light grey dots on the wave examiner tool get cut in half at the last vertical line. This leaves half of the dot behaving normally and the other half remaining in place. This is not effected by screen or scene. The frozen half dot moves up or down to a new frozen position when the target tools are moved.
Steps to reproduce:

1. Open the sim on firefox and go to any screen and scene
2. Pull out the wave examiner tool
3. Start a wave and make sure the targets are in position to pick it up
4. Move one of the targets to a new location

Screenshots:

Troubleshooting information (do not edit):

Name: ‪Wave Interference‬
URL: https://phet-dev.colorado.edu/html/wave-interference/1.0.0-dev.51/phet/wave-interference_en_phet.html
Version: 1.0.0-dev.51 2018-12-12 03:47:24 UTC
Flags: pixelRatioScaling
User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:64.0) Gecko/20100101 Firefox/64.0
Language: en-US
Window: 1536x760
Pixel Ratio: 2.5/1
WebGL: WebGL 1.0
GLSL: WebGL GLSL ES 1.0
Vendor: Mozilla (Mozilla)
Vertex: attribs: 16 varying: 30 uniform: 4096
Texture: size: 16384 imageUnits: 16 (vertex: 16, combined: 32)
Max viewport: 32767x32767
OES_texture_float: true
Dependencies JSON: {"assert":{"sha":"928741cf","branch":"master"},"axon":{"sha":"73e761ec","branch":"master"},"brand":{"sha":"1fd6682e","branch":"master"},"chipper":{"sha":"61bc739b","branch":"master"},"dot":{"sha":"b45eafe8","branch":"master"},"griddle":{"sha":"914c9215","branch":"master"},"joist":{"sha":"5a013a46","branch":"master"},"kite":{"sha":"f3e96e5b","branch":"master"},"phet-core":{"sha":"86dec8cc","branch":"master"},"phet-io":{"sha":"a267fdb1","branch":"master"},"phet-io-wrapper-classroom-activity":{"sha":"5dea7f54","branch":"master"},"phet-io-wrapper-hookes-law-energy":{"sha":"b42eaef7","branch":"master"},"phet-io-wrapper-lab-book":{"sha":"b884e9c1","branch":"master"},"phet-io-wrappers":{"sha":"d5b42848","branch":"master"},"phetcommon":{"sha":"869b2561","branch":"master"},"query-string-machine":{"sha":"e4f9e8e8","branch":"master"},"scenery":{"sha":"a18ce7f1","branch":"master"},"scenery-phet":{"sha":"56df5b6d","branch":"master"},"sherpa":{"sha":"a1f5e867","branch":"master"},"sun":{"sha":"38ed71af","branch":"master"},"tambo":{"sha":"746fbd32","branch":"master"},"tandem":{"sha":"c7a56e2e","branch":"master"},"twixt":{"sha":"e38c70ed","branch":"master"},"wave-interference":{"sha":"bfce593d","branch":"master"}}

[samreid]

Does this happen on Mac Firefox?

[KatieWoe]

Just checked 10.14 Firefox and it did not.

[arouinfar]

@kathy-phet was able to reproduce this in Win7/latest Firefox. The problem did not exist until she upgraded to the latest version of Firefox, so this looks like a browser bug.

@ariel-phet says let's defer this issue for now. We can come back and check during rc and see if a newer version of Firefox has fixed the issue.

@samreid would like to spend 30 minutes to investigate first, though.

[KatieWoe]

@samreid it is on Mac. I just realized that the Mac I had tested on was not up to date. Version it worked on = 63.0.3. After update (64.0) it is broken.

[samreid]

Same for me:

Working in Mac Firefox 63.0.3 (64-bit)
Broken on Mac Firefox 64.0 (64-bit)

[samreid]

Mac Firefox 63.0.3 (64-bit)

[samreid]

Mac Firefox 64 (64-bit)

[samreid]

Proposed workaround committed, @KatieWoe can you please test?

[KatieWoe]

I am now see this happening at the top of the graph. Not fixed

[samreid]

@jonathanolson can we schedule a time to investigate this?

[kathy-phet]

@samreid - Since Firefox introduced this bug, lets not prioritize it for v1. We can fix it if firefox doesn't fix it by v2 perhaps.

[kathy-phet]

But perhaps undo the last commit, because it made it worse.

[samreid]

Reverted, putting on hold until 2.0.

[KatieWoe]

@samreid @ariel-phet I saw something new in phetsims/qa#264 on firefox. Sometimes it appears as above, but I have also seen the dots remain intact but appear to be passing behind some object at certain points. This was seen on the Waves screen, light scene, when the graph is selected. I believe the graph is the determining factor. I doubt this changes the priority at all.

[KatieWoe]

@samreid @ariel-phet
Firefox 65 was just released and I checked this issue out of curiosity. It does seem to have resolved itself (I only looked for a few seconds). Would you like this issue closed?

[samreid]

I tested on Mac/Firefox 65 and I also don't see the problem. I think it would be OK to close this issue, but let's double check with @ariel-phet first.

[ariel-phet]

Agreed, closing