Good day, there is a modal window, in it a block with scrolling in Mozille when scrolling at the slider appears a black frame, which disappears after a while (a couple of seconds)

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Why does it appear and is it possible to somehow fight this?) In other browsers, all the rules

    1 answer 1

    Solved The point was that for positioning on the center of the screen, the transform property was applied to the modal window. Because of this, everything seemed to be crooked and the frame of the scrollbar did not coincide visually with the strip. The solution is to shift the window using negative margins.

    It was crooked because the window size is an odd number of pixels, with a shift of 50%, a half pixel is obtained. Another solution is to make the dimensions even.