I work with several Arduino board.
I should want have different color when I use different instance of Arduino IDE, as I have different port COM.
Do not confuse instances and windows. An instance is when opening IDE.
In one instance with file/open I can open several windows having all same port COM, same Serial Monitor.
If I open several instance, for each I can define one different port COM and have one specific Serial Monitor (and opening multiple windws).
To find witch Serial Monitor works witch what instance of Arduino IDE, I think it is easier if they have same color.
On each Arduino board I will past a same colored electric ribbon as Arduino IDE.
It is not about font color or backgroud color, but only the color of horizontal separation lines (top or head, botton or foot, and line that which changes color when having a compilation error).
have downloaded source, but it is too technical and too big ... Too many word "color" found and I do not know witch colors code #?????? are used in IDE.
Maybe a find/paste wil be enough to make a blue or green or yellow IDE named arduino_blue-1.8.2 or arduino_green-1.8.2 or arduino_yellow-1.8.2 ..
Not a bad idea as a foundation, but single instance multi tab would be better IMO.
Assign a sketch to a device by id/serial might be something more useful, so no matter which port the device is using the sketch gets loaded up on the correct device.
With this in place if you over-ride from the tool menu then the option to update the sketch settings should be shown.
This is just ideas from me, I'm not a c developer, just getting started with Arduino so the changes required are far beyond my experience.
Wrapping that in some sort of UI and code to actively change the colors is a more complicated issue, but perhaps this will be a useful clue to someone. (the "linestatus.bgcolor" is controlled by lib/theme/theme.txt, which is user-editable, but not a value that can be changed at runtime, nor saved...)
If I understand correctly, this thread and your issue report:
is primarily about automatic color coding of each instance of the IDE and the Serial monitor associated with that instance. Unfortunately that seems like it would be fairly complex to achieve and the Arduino developers have no immediate plans to implement this feature.
However, in your issue report you had also asked:
If it is not important for developper, maybe it is possible to define this in style file or maybe I can compil an IDE_Arduino_red, an IDE_Arduino_yellow, an IDE_Arduino_green, etc. How can I do it ? Please explain me.
It is possible to customize the coloration of the IDE by editing the theme.txt and default.xml files. By editing the theme of each of three installations of the Arduino IDE (or really only two of the three since one can be left default) you could easily achieve something like what is shown in your screenshot above. I have attempted to document the various theme settings here:
Unfortunately it does not appear that it is possible to customize the coloration of the Serial Monitor via the theme files.