Comment 2 for bug 229966

Selecting 'eliminate dead keys' variant does solve that particular problem: AltGr-4 now shows ~ directly, but it also implies that á é í ó ú cannot be typed. Previously (up to ubuntu 7.10) ´ (character to the right of ñ) was composed tilde, which followed by a vowel would print one of ( á é í ó ú ) symbols. At the same time AltGr-4 did print ~ symbol. To compose ~ with another char you could use a combination (Ctrl-ñ IIRC) followed by the second character.

With the current changes, either you cannot type á é í ó ú easily (which are required characters in spanish) or you cannot type ~ with just a single key press. Disappointing for programming in C++... moreover when you have grown used to it for years.