[SOLVED it DOESN'T] Why does changing the comport in a 2nd instance of Arduino-IDE change the Comport in instance 1 too?

Hello everybody,

since one week ago I used Windows Arduino IDE 1.8.13.
Now I'm using Windows Arduino IDE 1.8.16 in this way

I have two ESP8266 connected to my computer. One ESP8266 on COM-Port 16
the second ESP8266 on COM-Port 17

I start a first instance of the Arduino-IDE and adjust COMPORT to 16.

No I start a second Arduino-IDE and adjust the COM-Port to 17
but the COM-Port of the first instance changes to COM-Port 17 too?

In Version 1.8.13 this was possible.

Do I have to do something different to make this work again?

best regards Stefan

You must start a completely new instance. You cannot use File, New to create another window of the current instance.

IF you are starting a new instance, I don't know what is happening. I have never seen that.

This is what I'm doing.
a brand-new double-click on the desktop-icon for Arduino-IDE 1.8.16

Wow, I don't know. I use 2 (or more) instances quite often when working with Bluetooth or rf24 radios.

Does it work right with an older version of the IDE?

That's probably because both instances take the COM port information from the same config or settings file. Ideally you should be using only one instance primarily because of the COM port, and the IDE is not designed to work with two or more COM ports (as in connecting two arduino boards to different USB ports). Anyways if one IDE instance is communicating with the port the other will find it as busy or inaccessible.

I, respectfully, beg to differ. I have had 2 or more instances of the IDE open at the same time and connected to different serial ports while working with wireless stuff for years with no trouble.

Point taken. Thank you.

I must have mixed up something. I carefully re-tested it with 1.8.13 and 1.8.16

I tested it with windows IDE 1.8.13:

double-click on Desktop-Icon for IDE 1.8.13
opening a sketch1.ino
adjusting comport to 16

double-click on Desktop-Icon for IDE 1.8.13
opening a different sketch2.ino
adjusting comport to 17

comport in instance with sketch1.ino (primary adjusted to comport 16 stays on comport 16)

croschecking with windows IDE 1.8.16:

double-click on Desktop-Icon for IDE 1.8.16
opening a sketch1.ino
adjusting comport to 16

double-click on Desktop-Icon for IDE 1.8.16
opening a different sketch2.ino
adjusting comport to 17

comport in instance with sketch1.ino (primary adjusted to comport 16 stays on comport 16)

and both worked as expected.

Thank you all for replying