A user got on to me today saying that they can no longer filter by column in a list. The only column that appears in the filter pane is the default 'Title' column. When she adds a new column it gets added to the pane, it just doesnt pick up pre existing columns. The list only has ~800 items so it's in no way over the threshold. She is also unable to see 318 items out of the ~800. No permissions were changed and she had full control yesterday. Any ideas?