Hi,

To remove this sidebar, please open pennews/editor-style.css - find add remove this code:

html .mceContentBody:after {
    content: 'SIDEBAR';
    color: #ccc;
    position: absolute;
    right: -50px;
    top: 0;
    display: block;
    width: 10px;
    word-break: break-all;
}

and this code:

html .mceContentBody:before {
    content: '';
    position: absolute;
    top: 0;
    bottom: 0;
    right: -20px;
    border-left: 1px dashed #ccc;
    width: 1px;
}

After that, go to again the editor and Press Ctrl + F5 to clearly the cache of browser to see the changes.

Best Regards,

PenciDesign

Hi,

Please send me your website management information ( admin url site, username and password  ). I will add more this code help you.

Best Regards,

PenciDesign

Hi,

I added more code remove this sidebar which is appearing in wp post editor into your childtheme's "function.php" file as screenshot http://prntscr.com/lenbyd

You can check it again.

Best Regards,

PenciDesign

Hi,

I remove space white  in the editor. You can check it again. Before check, please clear cache.

Best Regards,

PenciDesign