Period timer refuses to measure period

[phet-steele]

1. Go to the Lab screen and enable the period timer.
2. Enable the second pendulum.
3. Set the second pendulum swinging, don't touch the first (blue) pendulum.
4. Press the play button on the period timer.
5. Press the little switch on the period timer to switch it to measuring the period of the second pendulum.
6. The period will not be measured, and clicking the u-turn looking restart button then the play button again still doesn't measure the period.

Video: https://drive.google.com/file/d/0B3HJopSo_QqLVVFEaTg1M0R4NE0/view?usp=sharing

Tested on Win 8.1 browsers.

Troubleshooting information: Name: Pendulum Lab URL: http://www.colorado.edu/physics/phet/dev/html/pendulum-lab/1.0.0-dev.4/pendulum-lab_en.html Version: 1.0.0-dev.4 2015-06-04 17:46:07 UTC Features missing: touch User Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0) Gecko/20100101 Firefox/38.0 Language: en-US Window: 1366x633 Pixel Ratio: 1/1 WebGL: WebGL 1.0 GLSL: WebGL GLSL ES 1.0 Vendor: Mozilla (Mozilla) Vertex: attribs: 16 varying: 28 uniform: 1024 Texture: size: 16384 imageUnits: 16 (vertex: 16, combined: 32) Max viewport: 32767x32767 OES_texture_float: true Dependencies JSON: {"comment":"# pendulum-lab 1.0.0-dev.4 Thu Jun 04 2015 11:46:00 GMT-0600 (MDT)","assert":{"sha":"903564a25a0f26acdbd334d3e104039864b405ef","branch":"master"},"axon":{"sha":"7de4a27be4b322b71c5f5046df193a03ccf0f161","branch":"master"},"babel":{"sha":"8725cd18114c1307057c465a0762a3cf8f1cb1b9","branch":"master"},"brand":{"sha":"b3362651f1d7eddb7f8697d02400472f97f9d140","branch":"master"},"chipper":{"sha":"c7d6ea5f9bef6e3882309af56ad409908dd28878","branch":"master"},"dot":{"sha":"a6a50c92c4cda5f8a3371d8c357ea565b7e7bd6c","branch":"master"},"joist":{"sha":"55fd6884039c5ef2f2145093c8530beab5490233","branch":"master"},"kite":{"sha":"b915f3b160744e4833d177dc38e74e4cbc912883","branch":"master"},"pendulum-lab":{"sha":"2b4cf70e4a8a88b37882b1643d44155a806508ab","branch":"master"},"phet-core":{"sha":"23834d107dc1cb368c00901c76927b712b9caa10","branch":"master"},"phetcommon":{"sha":"bb92c52cd90fdaa0c2a746fea82594afd439b4db","branch":"master"},"scenery":{"sha":"f09eddb7393946fcbedb63ebf6b88d1785c91bfc","branch":"master"},"scenery-phet":{"sha":"7ffc5a1a36e0afe36d035d0367078b3558fd157f","branch":"master"},"sherpa":{"sha":"ae2168a85ceb4094c23cd47ba5fe8145375448eb","branch":"master"},"sun":{"sha":"c9087fbb0cdd83f79452330fec3b83f809e2c0d8","branch":"master"}}

[andrey-zelenkov]

Fixed period timer measure method. Reassign to @phet-steele for verification.

[arouinfar]

It looks like the behavior has been halfway fixed. The period can now be recorded if the period timer is reset and record/play is pressed again (end of step 6 in @phet-steele's description). However, if the period timer is in record mode, and then switched to pendulum 2 (step 5) the period will still not be recorded. Reassigning to @andrey-zelenkov.

[andrey-zelenkov]

Fixed path visibility behaviour in period timer measure method. Reassign to @arouinfar for verification.

[arouinfar]

Issue has been fixed, thanks! Closing.