I'm still using IDE Version 1.8.19 because I had too many bad experiences with IDE 2.0.X
No ! I'm not gonna change to 2.0.5 which has "so many bugs fixed"
I know IDE 2.0 can handle this but not in a way I want it to.
I'm often using two or three separately started instances of the Arduino-IDE to be able to have different devices connected at the same time and each IDE configured for a different type of microcontroller.
To make it very easy to see which IDE is what I changed the colors like you can see in the picture
having three batch-files that copy "different color-schemes"
The batch-files copy the color-defining configuration-files into one and the same portable Arduino-IDE-folder
By doing this the color-scheme gets updated. This means if I open another file with the "red" IDE
and the last started IDE was the yellow one the new window belonging to the red IDE will be yellow in the taskbar
Now my question is:
Is it possible to have three different portable Arduino-IDEs where all three IDEs use the same folder for
all the corefiles (= updating boards/cores with any one of the three IDEs means updated for all
all three IDEs use the same library-folder (=updating libraries with any one of the three IDEs means updated for all
By default a portable IDE installation installs libraries under the portable/sketchbook/libraries/ subfolder of the Arduino IDE installation, meaning that each portable installation has its own isolated collection of libraries. However, a shared collection can be accomplished by changing the "Sketchbook location" preference in each of the IDE installations to point to the same folder. Libraries are installed under the libraries subfolder of the sketchbook folder, so this will cause all the IDE installations to share the same libraries.
Once you add the portable folders, you will find that Boards Manager installations are made to the portable/packages/ subfolder of each Arduino IDE installation, meaning they are not shared.
It is not possible to configure this path in Arduino IDE 1.x. The only workaround I can think of is eschewing Boards Manager and instead making manual installations of the required boards platforms under the hardware subfolder of the sketchbook folder. Arduino IDE will also recognize platform installations made to that location. Unfortunately, it is not so easy to install tool dependencies of platforms manually so you might it challenging to make completely shared installation of packages. You mention "corefiles", and if you really are only interested in sharing cores, then there is no problem. But more likely you are using the term "corefiles" when you really mean "packages". Cores are a component of the platform, and platforms are a component of the package, along with tools, but there is an unfortunate practice of using the term "core" instead of "platform" or "package" in the Arduino world.
The only problem is Arduino IDE loads the platform configuration files on startup. So it won't recognize any changes made to those files under the portable/packages folder during an IDE session. So if you installed or updated a platform via Boards Manager in one IDE instance, other IDE instances running at the same time would not reflect that change until after you restarted them.
