Scroll issues with toolbar and statusbar on LTR and RTL docs

[bayramcicek]

Describe the Bug

LTR docs:

• Scrolling toolbar and statusbar with Shift + mouseWheelUp/Down does not hide/show the scroll right/left buttons correctly.
• Therefore right/left buttons ovarlap with other elements

RTL docs:

• all LTR issues exist.
• scrolling with clicking on the buttons sometimes does not show/hide buttons. (this works well on LTR docs.)
  • the reason: this._RTL always returns undefined. So we couldn't know if the doc is RTL or LTR.
• scroll-right buttons' arrows are not aligned well.

Screenshots

LTR:

Peek.2025-01-15.15-17-en.mp4

• no misaligned scroll arrows - good

---

RTL:

Peek.2025-01-15.15-18-ar.mp4

• misaligned scroll-right arrows - bad

Online

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