"Update Notice - What's New button" invisible when using different QF theme than flat style

[RealRaven2000]

Observed Behavior
When using the theme "toolbar buttons" with the default theme then the QuickFolders button that opens the Splash screen appears as white text on light background:

Expected behavior
The button should look like this:

[RealRaven2000]

It appears the setting display: -moz-inline-box; for the #QuickFolders-LabelBox causes this problem. Here is a version with a fix that looks good with all QuickFolders themes.

QuickFolders-mx-5.7pre6.zip

To install this version, download the zip file, and then drag into Thunderbird Add-ons Manager.

[RealRaven2000]

Fixed in 5.7, released on ATN today.