Room for improvment. You only see the formatted text in the sidebar. Personally, i dont like working in the sidebar. When you save it, It saves it as 1 line. Might as well copy the code into a code editor and paste it back in. I want to see the formula pannel with line breaks and indents to be converted to spaces up top. It would be better if you just run the fucntion from the menu and it formats your formula as such. Also your script removes spaces in quotes(text i want to return in the cell), i would make a rule that omits formatting for things inside " ". When I copy paste code in from another app it keeps the indent formatting so i know its possible. I realize sheets doesnt know what cell you are working in until you made the edit. Maybe you would have to make a function that works with onSelectionChange to identify the current cell and then when you run the formatting script it will apply to whatever is selected. Food for thought. Could easily be a 5* extension :)