Eudora - 5.1b20

There is a poorly iconed pull-down menu above the scroll arrow at the upper right of the message list pane. In this menu are two occurrences of the item "Who." The top one enables Recipients; the bottom one enables Senders (I have only the bottom one checked). This feature is by no means clear - I worked it out through trial and error. The first trick is to find the blasted pull-down menu. The Recipients/Senders feature is a Penelope add-on item. It's not present in the Thuderbird or even Eudora without Penelope.

By the way, I've found that Penelope has serious problems in OS X 10.6.1. With a message selected in the message pane, any keyboard input moves one or another message to the trash. If you have the trash in the message window, keyboard input will delete a selected message entirely. As a result, I have had to disable Penelope in Eudora, which rather defeats the purpose of using the Eudora version of Thunderbird. I have not reported this issue because filing bug reports for Eudora remains, as it has been for a very long time, incredibly tedious. As always with Eudora, you just have to hope they will find and fix the bug eventually - I call that the Eudora tax. Even though the program is now free, that tax remains. The developers continue to hide behind a screen of open source gobbledegook. Given that they make user feedback so difficult, I wonder why they even bother with the Eudora/Penelope project. Given the long intervals between updates, they clearly don't bother very much.

In the original Eudora, it was possible to fully edit the contents of all mailboxes. Is this capability retained in the new version?