@samerafach Thanks for reporting this issue!
I can see the side-scrolling issue on your site linked above: http://link.afach.de/rtlproblem
... but I cannot recreate it when using Twenty Fourteen on a test site.
I tried working through your site in the Element Inspector, deleting items to rule them out -- the side-scroll appears to be coming from:
<div id="stcpDiv" style="position: absolute; top: -1999px; left: -1988px;">ShareThis Copy and Paste</div>
I'm not sure where this is coming from, whether it's something you can edit directly, or something in a plugin. If you can edit it directly, changing the left: -1988px to right: -1988px should fix it, like:
<div id="stcpDiv" style="position: absolute; top: -1999px; right: -1988px;">ShareThis Copy and Paste</div>
... and if you can't edit it directly, you should be able to change is using some custom CSS:
#stcpDiv {
left: auto !important;
right: -1988px !important;
}
@parsmizban thanks for the patch! It sounds like the issue was with the video player on the whole, not specific to Twenty Fourteen -- there was another ticket opened here by @samerafach: #36185
It has been closed due to lack of activity, but when I test it, it looks like the styles for .mejs-offscreen have changed (removing the left placement), so this should no longer be an issue:
.mejs-offscreen {
border: 0;
clip: rect(1px,1px,1px,1px);
-webkit-clip-path: inset(50%);
clip-path: inset(50%);
height: 1px;
margin: -1px;
overflow: hidden;
padding: 0;
position: absolute;
width: 1px;
word-wrap: normal;
}
However, if this issue persists, please reopen #36185!
I'm going to close this issue, as I can't recreate either issue with a fresh install of Twenty Fourteen. But please let me know if there are any questions at all!