STR:

• Set folder pane to "Show total message count" and/or "Show folder size".
• Create test-folder and copy a few message to it.
• Select test-folder.
• In test-folder, mark at least one message as unread.
• The unread count appears, as expected, beside test-folder.
• Note that total message count and/or folder size doesn't appear. Only unread count.
• Collapse then expand the account folder tree doesn't show total messages and/or size.
• Repair of test-folder also doesn't show total or size.
• Finally, restart TB. Only then does total messages and/or folder size for test-folder appear.

I noticed this testing moving and copying folders while working on Bug 1831759. But it really has nothing to do with moving or copying a folder. Just manually creating a new folder, as described in the STR, illustrates the bug.

Adding a "toggle" allows the total number of messages to appear OK.
But if you move a folder within the same server, you have to select the folder before the total number of messages appears. Move/copy across servers doesn't require the folder to be selected to see the total with this diff in place.
I tried adding a similar call to "toggle" the folder size but that didn't cause the folder size to appear automatically.

A workaround for this without code change is to select the new folder and manually toggle the folder header fields "show total" and "show folder size" off to back on.

Sol, can you take this and ensure that the "show total" and "show folder size" is showed also for newly created folders?
You can use Gene's patch as a start but most likely we need to use our isItemVisible() methods to see if the newly created folders need to show the total count and folder size based on what we have in the xulStore.