How do I update library h-file in arduino create online editor for SSD1306?

I'm working on a sketch that includes i2c with a SSD1306 OLED and need to update a constant in Adafruit's h-file in the library. I need to set the height of display/display type in the h-file in the library.

How can I do this in the online editor?

/Jonas

I am not sure what you mean by "online editor"

Most people use the regular Arduino IDE to edit their sketches (.INO files)
The IDE will not let you edit Library files.

If you really do want to edit a Library file, you should use an external text Editor. e.g. NotePad++
Browse for the file in question. Edit it. Remember to Save it back to your PC.

Your Windows PC came with NotePad and WordPad.
NotePad does not understand linefeeds
WordPad might think you have a Word Processor document. Be VERY careful.

You need a simple Text Editor that can understand ascii text with linefeeds. It must not add any extra formatting information.

David.

Hey,
The online editor is "Create" : create.arduino.cc
Iwant to modify library, too.
Have you found the way to do this ?
thanks