I am using the latest version of LyX and I am having trouble getting the limits to work at all. Ideally, I'd like to be able to place the summation limits above and below the sigma. However, at this point, I would settle for the less-pleasing-to-my-eyes variant of having the limits in the northeast and southeast corners of the symbol. However, try as I might, LyX does not want to place the limits anywhere. The "Change Limits Type" whose use I have seen recommended in various forums remains greyed out no matter what I do and the documentation does not provide any information I have yet found on how the process is even supposed to work in theory. On an admittedly editorial note, I am beginning to feel LyX is extremely lacking in documentation, which is unfortunate as I think it otherwise is a great application. Anyway, if Someone could point me in the direction of how to resolve this issue, I'd greatly appreciate it.