Alias mouse back/forward "thumb buttons" to PgUp/PgDn
Currently Evince implements the two buttons present on some mice (forward/back) to jumping back and forward in history, e.g. when typing a page number it allows one to get to the page they were on before.
While this feature is definitely useful (and unfortunately obscure for users who don't use these kind of mice), as a possibility it may be also interesting to have these buttons mapped to Page Up/Down for quick scrolling in documents.