Backbuttoning after navigating away always produces the saved old comment text. Closing the tab is irregular: if I open a new identical tab while still on the existing tab, it doesn't save; if I visit the closed entry by directly typing in the URL it doesn't save; if I hit the same link I hit to open the entry in a new tab, also in a new tab, it only coughs up the saved text occasionally. I haven't been able to establish what the pattern is.