I grew increasingly tired changing the column settings of the folders of my IMAP account in Thunderbird; I don't need the 'Read', 'Junk' and 'Thread icon' columns for example, but would like to have the 'Size' listed. However, I needed to change that for all of my dozens of mail folders...
Then I found the following solution (work in Thunderbird 3.1 and up). To apply the current set of columns to all folders:
- Right-click on the columns
- Select "Apply columns to..."
- Select "Folder and its children..."
- Select the root folder for your account
- Done! You have applied the set of columns to all folders in your account.