I can confirm all of elgonzo's 4 tests, but expecially test 4 clearly shows that there is a bug somewhere.3. Note how the width of the Name+Extension columns has grown.
4. Repeat this test (Click Configuration -> Save position, restart TC, observe further growth of Name+Extension columns)
5. Rinse and repeat. After each iteration of this test you will notice that the width of both the Name and Extension columns grows more and more and more..
This constant growing of the Name+Ext column only occurs when "Adjust tabs to window width" is disabled, it is not enough to just enable "Show file extensions directly after file name"