Disable dotted line in slideshow film! HOW?

This section is where? Where can I erase the dotted line in the slideshow movie.
I know jelzni the last picture, but do not need it.

Thanks for your help!

elem {
    width: 100px;
    height: 150px;
    margin-left: 4px;
    margin-top: 2px;
    margin-bottom: 2px;
    padding-right: 4px;
    <em><strong>border-right: 2px dotted gray;</strong></em>

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