Opening Serial Monitor changes port

Running 1.8.5 NB on a RasPi3
ssh -X me@raspi

So the Serial Monitor wasn't a problem until the last couple of days ago

I plug in my proto board with a 8266
From the command line I run "arduino"
up comes the last sketch(or2)

ls /dev/ttyUSB*
I get ttyUSB0
Tools->Port sel usb0
click on mag-glass and up pops the Serial Monitor
Double check Tools and "Port" is blank
ls /dev/tty...
USB1 ah...
Tools->Port usb1
Sketch->Serial Monitor
error: ttyUSB1 is not avail
and Port is empty - again
insanity is doing the same...........

Yes - Serial.begin (9600);
Yes - I am a member of dialout

I'm in twisty little passages all alike....

Forgot to say: usb<->ttl is a FTD1232 board. And it was working when I was programming a -12 but not with a -01.

I have the same question posted on the RasPi Forum. Seems I'm not alone

From the RasPi Forum

  • It will likely of be little comfort, but it seems that you're not alone... Serial Port selected disconnects after upload. Given that this appears to be a multi platform issue and not specifically an rPi issue, you might have better luck on the Arduino forum.

????????????

When programming a NodeMCU I don't have the problem. Only when I program a -01 via a FTD1232 board.