Bitmap eraser not working under certain conditions

Hi, I LOVE Toon Boom software. I experienced a very annoying bug. I was drawing some bitmap fireworks in Toon Boom in the Drawing mode. It was easier to draw them when I went into Preferences\General\Colours\Edit Colours\Drawing\Others\Background\ and set it to black instead of the default white. I was able to draw about 10 frames worth, using the drawing and erasing bitmap tools. After cloning the layer a few times, I duplicated another version of the layer to edit the art frames a bit. I returned to the Drawing View, but the eraser would not erase any of the art. The bitmap brushes would still apply color and the cutter tool could be used to cut and delete the bitmap pixels, but the eraser wouldn’t do anything. The eraser’s opacity was up to 100% and I tried a few erasers, but nothing I did could make the erasers work. I even started a brand new file. Same problem. I was drawing on a bitmap layer and applying color just fine, but none of the bitmap erasers would do anything.

I finally found a solution to the problem. I went back into my settings and turned the Background white instead of black and now the bitmap eraser works just fine. I don’t understand why. I used all sorts of colors like red and green, but the eraser simply wouldn’t erase as long as the background color was set to black in the Drawing View. I solved my problem, I just figured I would post this here in case other people have the problem. I’d be interested to know if you can replicate the problem. Thanks Toon Boom! Can’t wait to here about TBH 14!