I think Document List Panel (Doc Switcher) could be improved with just a few very easy options.
1) Sometimes, when I try to open the first file in the list, I mistakenly click in the column names of the Doc Switcher, making it to sort by Name (or by Ext.). That sucks, because I can't revert it to the Order Sort again.
My suggestion is either you add a 3rd column "Order" (1, 2, 3...) or add it to right-click context menu in the column names.
2) Since you moved the file extension to another column, I never liked it. it makes it pretty hard to distinguish files sometimes, if the "Name" column is very expanded. I have a lot of files with the same name, but extension is different (file1.php, file1.css, file1.js), and that would be very convenient if the extension appeared also in the "Name" column.
3) That would be good if we could hide some columns like "Ext." (once extensions can be seen in the "Name" column), or simply have the old version of Doc Switcher as an option.
4) It would be convenient if we could drag the files to sort as we want, just like the horizontal tabs on the top. If this was possible, I would simply hide the tabs on top. That would save a bit of vertical space in my laptop screen.