TypeError : 'previousElementSibling'

### Description
Hello, I got a new error message😥.
I think this problem is caused on mobile size.
The problem occurs when I leave the main page(applied fullpage) and moves to another page.
It doesn't keep happening, it happens occasionally. So I don't know the cause.

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### +) Another issue
On mobile size, when I click the dragAndMove slidesNavigation, I got the error message.

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##### code
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Also I found the another issue, then I updated the version for @0.1.35