It would be nice to have a button for marking all messages in a folder as read. I conceive it as the “round dot” on mouse-over for single messages in the message list. It could be in the toolbar as well.
There should be a confirmation box to prevent unwanted action.
As of today you have to right click → toggle all read. This is not smooth in my opinion. Right clicking should always be a secondary choice.
The function is especially relevant for junk mail and deleted messages.
Unfortunately there are no buttons for folders. None at all. We don’t provide a toolbar for that purpose.
Instead, like other applications we offer the option to mark as read through right-click either on the messages or the folder, or you can select all the messages and use the Mark as Read toolbar button. Toolbar buttons do apply to messages
Still, as it is a very commonly used function I guess (I personally use it on a daily basis), it would be nice with some shortcut.
Could be a symbol, which becomes visible only on hovering over the folder names in the folder list. Like the dot, flag and bin appearing on hovering over message titles.
Or maybe the number for unread messages next to the folder names could become interactive (and change appearance on hovering over).
That was just my thoughts.