> Using both calculator and emulator I can't use FORMAT OR STYLE button in the correctly way.
Currently, the way it works is that it either applies to the current selection/word/node, or what will be coming up when typed . If you have "123+456" and change the size, it will change all the text. If you have "123 456" it will only change the "456". Spaces or new lines stop the node.
> Try to write H2O as a chimical formula. If you use the sixth option of the style-options menu you will notice that It does not work.
It works if you select the text (hold down for 1 sec then drag to select), or if you have your 2 separately. Together, it will treat them as 1 "unit" and apply it to everything.
> If you try to use the format menu, choosing an other font size, each character will change.
Correct. That is the current behavior when you have a single "word" like H2O with no spaces or breaks.
> If it works for you, could you tell me how you write H2O?
It does, but I agree there needs to be some UI improvements here. Hopefully, someone will let the developer who wrote it know so they can fix it sometime... I wonder who I can blame for this problem area... ;-P
Once you have a single subscript 2, you can copy and paste it as desired. That will be your quickest option. A simpler alternative that I would recommend though if it really isn't formatting you want but just subscript/superscript for some numbers, you can use the superscript/subscript unicode characters quickly.
Go into the CHAR menu, press "MORE" and find the superscript/subscript. Those are actual characters and have no formatting involved. Alternatively, just copy and paste them from a suitable source.
TW