Sim dies after placing atoms on nature's mix screen

[phet-steele]

Pretty simple multitouch problem. With one finger grab an atom out of its bucket (on the Mix Isotopes screen) and with another finger switch to Nature's Mix. Place the atom you were holding into the play area. This kills the sim. This issue is possible on non-touchscreen devices with #33.

Tested on 1.0.0-dev.5 with iPad 2 iOS 9.2 (Witten). For phetsims/tasks/issues/488.

[phet-steele]

Troubleshooting information (do not edit):
Name: ‪Isotopes And Atomic Mass‬
URL: http://www.colorado.edu/physics/phet/dev/html/isotopes-and-atomic-mass/1.0.0-dev.5/isotopes-and-atomic-mass_en.html
Version: 1.0.0-dev.5 2016-01-26 23:09:01 UTC
Features missing: fullscreen
User Agent: Mozilla/5.0 (iPad; CPU OS 9_2 like Mac OS X) AppleWebKit/601.1.46 (KHTML, like Gecko) Version/9.0 Mobile/13C75 Safari/601.1
Language: en-us
Window: 1024x671
Pixel Ratio: 1/1
WebGL: WebGL 1.0 (OpenGL ES 2.0 IMGSGX543-124.1)
GLSL: WebGL GLSL ES 1.0 (OpenGL ES GLSL ES 1.00)
Vendor: WebKit (WebKit WebGL)
Vertex: attribs: 16 varying: 8 uniform: 128
Texture: size: 4096 imageUnits: 8 (vertex: 8, combined: 8)
Max viewport: 4096x4096
OES_texture_float: true
Dependencies JSON: {"assert":{"sha":"d4909677","branch":"master"},"axon":{"sha":"5a39ec57","branch":"master"},"babel":{"sha":"db982666","branch":"master"},"brand":{"sha":"8c6f9c04","branch":"master"},"chipper":{"sha":"57c99807","branch":"master"},"dot":{"sha":"ddf82014","branch":"master"},"isotopes-and-atomic-mass":{"sha":"3d0c3bb9","branch":"master"},"joist":{"sha":"4c228a32","branch":"master"},"kite":{"sha":"4a947119","branch":"master"},"phet-core":{"sha":"874a703d","branch":"master"},"phetcommon":{"sha":"3db92af3","branch":"master"},"scenery":{"sha":"953fe860","branch":"master"},"scenery-phet":{"sha":"e903fad2","branch":"master"},"sherpa":{"sha":"bf82eb95","branch":"master"},"shred":{"sha":"c1d4863f","branch":"master"},"sun":{"sha":"45c7d334","branch":"master"},"tandem":{"sha":"5388a9e4","branch":"master"}}

[phet-steele]

Related problems not dealing with the Nature's Mix (and the sim doesn't die). I don't think these warrant their own issue since they are consequences of the same above procedure.

Both on Mix Isotopes screen:

• After picking up an atom, switch to slider view and place the atom down. This doesn't break anything, but shouldn't be allowed:

• After picking up an atom (preferably Argon-40), switch to a different element (preferably Hydrogen). Placing Argon in this play area causes the scale for Average Atomic Mass to increase dramatically and resize the panel:

[aadish]

currently not handling multitouch

[KatieWoe]

This was seen again in phetsims/qa#300. As noted above it is in the published version. However, it seems rather easy to do with the potential of crashing the sim. So I wanted to highlight it in this rc.