Apart from that, I was kind of disappointed that the "goto file" only lists Geany open documents rather than the project's documents -- maybe you'd like to add that?
Done in the last commit - open files are sorted before project files and also non-open project files don't have any icon in front of them to distinguish them from the open files.
Also, I hoped to be able to go to a specific file's line, not only in the current file -- but that's probably less useful in practice.
Not done now, possibly in the future.