While paused, blocks jump out of beaker when beaker is moved

[kellywurtz]

For phetsims/qa#268:

Test device:
Macbook

Operating System:
MacOS 10.14.2

Browser:
Chrome

Problem description:
While paused, dragging a beaker with blocks in it causes the beaker and blocks to be separated. The beaker jumps to the side while the blocks stay in place.

Steps to reproduce:

• Pause sim
• Drag block (or two) into either beaker.
• Move beaker.

Screenshots:

[KatieWoe]

Likely related to, or even the same as #196

[jbphet]

@chrisklus and I talked about disallowing dragging of blocks and beakers while paused, and I just discussed this with @ariel-phet, and he's cool with it. He just suggests that we make the pause button a bit smaller to call more attention to the change of states. We decided to essentially "split the difference" between the size of the play button and the step button.

[arouinfar]

@jbphet @ariel-phet I was discussing this a bit with @chrisklus, and I think it's a bit unprecedented to make something unpickable when paused. This may also have some unintended consequences for keyboard nav later down the line. I am fine with this solution for 1.0, but I don't think it's ideal.

I think a more natural alternative would be to simply unpause the sim when the user starts dragging blocks or beakers. We did this with the wrench in Wave on a String. If the sim is paused, dragging the wrench will unpause the sim.

[ariel-phet]

@arouinfar agreed, would be good to have a better solution in place for 1.1

[chrisklus]

@arouinfar @ariel-phet it's equally easy to 1) make the beakers and blocks unpickable while the sim is paused, or 2) make the sim resume playing when when a beaker or block is grabbed.

Sounds like @arouinfar is leaning towards the latter, what is your preference @ariel-phet?

[ariel-phet]

@chrisklus I am fine with (2)

[chrisklus]

@ariel-phet cool, thanks. Would you still like the pause button to be smaller, and if so, should the pause button on the second screen match that size?

[ariel-phet]

@chrisklus yes, I think a bit smaller would be good, and yes, match the second screen. I think it generally looks good when then button appears to "grow" in case someone hit it by accident.

[arouinfar]

I think it generally looks good when then button appears to "grow" in case someone hit it by accident.

Ah, I just now understood what @jbphet meant by:

He just suggests that we make the pause button a bit smaller to call more attention to the change of states.

@ariel-phet I'd have to disagree. While it's true that some sims do have a play button that is larger than its corresponding pause, I have always found it to look a bit strange. Given the placement of the playback buttons in EFAC, I'm not particularly worried about accidental presses. I'd rather not include this feature in 1.0, but I will open a separate issue for discussion for 1.1+.

@chrisklus please proceed with option (2), and unpause the sim when the blocks or beakers are moved. For now, let's leave the playback buttons alone.

[chrisklus]

Implemented, could @KatieWoe, @arouinfar, or @ariel-phet try this out please.

[KatieWoe]

I'm ok with this

[arouinfar]

Looks good @chrisklus.

[KatieWoe]

Found a case during phetsims/qa#293 that may cause problems for this solution. Multitouch. If you pause the sim while still holding an object, you will still be able to drag that object around while the sim remains paused. Easiest to do on a touch screen like an iPad. Haven't seen any issues arise from it yet, and it is a bit more of an edge case. So feel free to close unless you think something more should be done.

[chrisklus]

@KatieWoe I'm not too worried about this. Once the user lets go, as soon as another block or beaker is touched, the sim resumes, right?

[KatieWoe]

@chrisklus Yes

[chrisklus]

@KatieWoe cool, thanks. I'm okay with closing but let's wait for more opinions first.

[ariel-phet]

Yes, I think OK to close. We generally do not worry too much about some of these multitouch edge cases unless they have the potential to wreak havoc pedagogically or crash the sim horribly. Closing