A type coloumn in the open dialog would be very useful. Especially for applications which handle many file types. E.g Gedit. You can filter by text files but that will still include any file with text encoding and say you're looking for all the .pl files in a large directory of text encoded files (such as .txt .sh etc) you are not able to group them by the type. If you're lucky all the .pl files have simular modified by dates and you can group them that way.