Now I see what you mean. I moved my char window into a non-transparent window to stack them and the stack did not become transparent. I unstacked them, enabled transparent background for the other window, stacked the char window into the now transparent window and the stack become transparent. When I unstacked the char window, it remained transparent and even stacking it back into a non-transparent window does not change that. And there is no option in the Char window to turn off transparency. Fabulous.