Same Problem in older versions.
The only account 'movement' is select default account.
The problem appears using different folders at each account.
Is not a problem of priority, only a visual problem.
The only way to choose the order is the order of installation of the
accounts.
Perhaps moving (drag and drop) only in "accounts settings" window could
help. Moving in "Folders view" could cause "accidents"

# 358680: thunderbird: Play new mail sound without hanging Thunderbird.
forwarded 358680 https://bugzilla.mozilla.org/show_bug.cgi?id=250186

# 363816: mozilla-thunderbird: "columns to display" should include "Date Received"
forwarded 363816 https://bugzilla.mozilla.org/show_bug.cgi?id=216033

# 363817: mozilla-thunderbird: Add an "empty folder" option in Junk folder
forwarded 363817 https://bugzilla.mozilla.org/show_bug.cgi?id=189911

# 363818: mozilla-thunderbird: news - Impossible to sort messages by 'Labels'
# contains two issues ... cloning and forwarding auto labelling issue
clone 363818 -1
retitle -1 Auto-labelling of messages by inheritance
forwarded -1 https://bugzilla.mozilla.org/show_bug.cgi?id=207124

# 363819: mozilla-thunderbird: Thunderbird should allow creating custom header fields
# -> use extensions for this.
tags 363819 + wontfix

# 363821: mozilla-thunderbird: add SSL/TLS option to account wizard
forwarded 363821 https://bugzilla.mozilla.org/show_bug.cgi?id=221030

# 363822 mozilla-thunderbird: Thunderbird uses wrong preference directory
# ... I just wontfix unless comes up with a migration patch ( p<0.00001 )!
tags 363822 + wontfix

# 363824: mozilla-thunderbird: Can't change accounts order
# ... this is of course long known upstream.
forwarded 363824 https://bugzilla.mozilla.org/show_bug.cgi?id=61078

# 363823: mozilla-thunderbird: Add an option for "check for mail in all folders"
# this is a non issue I guess; however, an individual button will not be implemented
tags 363823 + wontfix

# 363825: mozilla-thunderbird: Should use /etc/mailname in setting up a new account
# this i far too unix specific that one might suggest this upstream ... so wontfix
tags 363825 + wontfix

# 363828 mozilla-thunderbird: default mail headers should also show "resent-from" and "resent-date"
# there is not enough space for making this default ... closing this bug.
tags 363828 + wontfix
close 363828

# 363834: mozilla-thunderbird: thunderbird should provide news-reader VP
# ... yes will add this ... tagging confirmed!
tags 363834 + confirmed

thanks


I changed your bugs state for housekeeping. Look above for a short
explanation what happened to your bug ... and remember to not cc all
bugs listed in current CC.


 - Alexander