Accidentally hit a keyboard shortcut that turned all of the thumbnails black

[mgilpatrick]

I've been working in TVPaint today and just now hit a keyboard shortcut that turned all of the thumbnails in the clip I am working on to black. What keyboard short cut did I hit and how can I get the thumbnails back.

I've tried to attach screenshots from the clip timeline

first screenshot shows the clip with the black thumbnails

Screen Shot 2020-02-02 at 5.49.55 PM.png (58.81 KiB) Viewed 13586 times

the second show another clip from the project that has normal thumbnails.

[Hironori Takagi]

Perhaps you hit "Shift-B"(chenge Background mode).

[2dbert]

..and if so, you just need to hit Shift B again to get a transparent background, and yet again to get back to your white background colour, one should maybe add.