File Manager progress bar appears white on white

[ane-gabriela]

When adding a file in the File manager the progress bar is white on white which makes it seem like the progress bar is missing.

Environment: Windows 10, XWiki 11.7 with MySQL 5.7 and Chrome 77 and Firefox 69

FYI - Issue also reproduced for a client, more info from Anca "This also seems like a bug of the FileManager application with a color theme that doesn't specify an explicit color for the headings.
There is an explicit CSS for progress bars in the file manager, for some reason and the color of the progress bar is taken from the colorTheme.titleColor and, when no color is specified in the flamingo theme for @headings-color , the value is "inherit". Since the progress bar is white, "inherit" inherits white."