Version:           1.8.2 (using KDE KDE 3.4.2)
Installed from:    Mandriva RPMs
OS:                Linux

When I want to create a new folder to store a message in, I right-click on Local Folders, which immediately closes my current folder.  Then I can create my new folder, though I can't see the mail message that inspired me to create the new folder.  Then I have to go back to whatever floder I was in and select it again.  Finally, I can move the message into the new folder.

Right-click should bring up the context menu for the folder.  Left-click should select the folder.  The latter is an action, the former requests a menu.  There is no reason that right-click should select the item, too.

Or, if you prefer, right-click can select the item so as to visually declare which folder is being acted upon, but the view should not switch to that folder if the user chooses a menu item.  This is probably the best approach.  Only jump to the new folder if the user releases the right mouse button while on the folder and not selecting a menu item or moving away from the folder.