The number of file types that Libre can open is impressive but this leads to a problem with the File Open dialog. Apart from the rather odd looking "All files" list, which fills the entire height of the display, the sheer number of options is a little overwhelming.

Would it be possible to have two drop downs, one for a category and then the other which lists the file types associated with that file type. It kind of already does that but the categories appear at the top of the list, i.e. "All files", "Text Documents", "Spreadsheets", followed by all the distinct file types. So the enhancement might look something like:
"All Documents" -- "All Files"
"Text Documents" -- "All Files"
                    "Open Office Document (.odf)"
                    "Word 2007 Document (.doc)"
                    "Plain text document (.txt)"
                    "..."
"Template Documents" -- "All Files"
                        "Open Office Template (.odt)"
                        "Word Template"
                        "Excel Template"
                        "..."
"Spreadsheets" -- "All Files"
                  "..."

and so on.