Recently I discovered that the sort order of the same file depends on the file type: In one case I stored the content as *.xml, in the other *.html. I'm using textpad 6. I thought sort order is influenced by the language setting, but obviously that's not all.
Can you tell us steps to reproduce this? Best would be as compact as possible, i.e. "create these three lines in two documents, then save one of them as .XML, the other as .HTML, then sort both." I can only use TextPad 8 for testing this.