SerialPlotter disappears unexpectedly

[chipaudette]

I was trying to use the SerialPlotter on the phone App, but if the Teensy sketch isn't ready for it, some unexpected things happen to the App. Specifically, the SerialPlotter page crashes and disappears. Weird.

Steps to recreate:

1. On the Tympan, put "BasicAgain_wApp" on the Teensy. Note that it asks the App to display the serialPlotter, but the sketch has no response to any of the serialPlotter's commands (which are ']' and '}').

2. Once the Tympan is running, start the App and connect to the Tympan

3. Once the App receives the Tympan's setup, swipe over to the SerialPlotter page

4. Press "StartPlot". As expected, nothing gets displayed because the Tympan sends no data

5. Press "StopPlot". As is NOT expected, the SerialPlotter page disappears. The App is still running, but that one page is gone.

This is not a high priority problem, but it also seems like it ought to be a relatively easy fix.