76.0b2 (64-bit) Linux Mint - Copies & Folders>Other fly out sub folders have no background

Thunderbird Beta
1

When selecting a folder from any of the Other: options on
the *Account Settings>*Copies & Folders page,
the fly outs that offer sub folders have no solid background and
are difficult to see.

Attachment of the issue added.

tbird-beta.png
tbird-beta.png785×395 74.7 KB

2

fixed in Version 77.0 beta 2