I just recently upgraded from 4.7.3 to 5.1.0. I bypassed the 5.0.x versions because of the multiple instance window placement issue which was fixed in 5.1.0.
One feature from 4.7.3 that I sorely miss in 5.1.0 is sorting by a selected column block. Specifically, going in to block select mode, selecting a number of columns and lines, then hitting F9 to sort. In 4.7.3, the selected lines are sorted based on the selected column range. In 5.1.0, I have to go out of block select mode, click on the first character where I want the sort to begin and note the column number in the status bar, select the number of columns I want to sort on, note that value on the status bar, then reselect the lines I want to sort, hit F9 to sort, then plug in the values I noted previously.
I am able to get it to work some of the time, but it is inconsistent. I have numerous files where it won't work. However, if I select all and copy to the clipboard and paste into a new document, I can sort on a selected block.
When it works, a dialog window opens with the title "Sort Selected Column". When it doesn't work, nothing happens when I hit F9 or use Tools->Sort from the menu.
I just figured it out. My default font for TXT files is MS Mincho. If I change to a different font, it works.
Is MS Mincho a variable-pitch font? Sorting on a selected column isn't available when you're using a variable-pitch font; when you are, it isn't clear exactly what a column is.
MS Mincho is a fixed width font used with East Asian languages. The corresponding variable width font is called MS PMincho. The ANSI characters <= 255 are essentially the same except for the backslash character which displays as the Yen currency symbol.