Using Windows 10 and chrome, composer pro's formula editor oftenly (around 30% of the time) presents a bug in displaying multiple lines of formulas. In those cases, the lines are displayed one way but are discovered in another way upon typing or being selected. The end result is that you can't just pick a place for the cursor and start typing, you need to go about finding out what really is typed "underneath" the displayed strings of text.
Check the attached snapshot for evidence (note how the selected text and the underlying un-selected text don't match -- what I call "ghost line breaks" aren't displayed, but the actual text is in another line, arranged differently).
This has happened ever since I can remember. Decided to report it today. Over time, I've learned that sometimes allowing line breaks manually, with spaces, can remedy the issue, but not always.