Jalview File Open dialog should have an "All alignment files" option by default to show all possible alignment files that can be opened

When File -> Input Alignment -> From File (or similar) is chosen the default folder is the last folder where I opened a file.

It is possible to get into a state where the default filetype is (e.g.) Fasta, but there are no Fasta files in the default dir (which might have contained a, e.g., Stockholm file).

In linux this means I am immediately presented with a folder and no visible files (in other OSes these files are shown but greyed out).

The "Files of Type:" dropdown list should contain, and default to, an "All alignment files" item that globs all the known extensions for alignment files (which could be automatically generated from known file extensions).

[Also note here that the "Recently Opened" box is unusable in Linux if it contains a file with a long path, which pushes all other filenames out of the box. I believe there are other plans for this!]