Mouse pointer strange behaviour related to timeline slider.

Steps:
1. Create a new Landing page.
2. Add a Schedule block.
3. Add a content item.
4. Try to move the slider 1 or 2 hours into the future or the past.
5. Observe the mouse pointer icon when hovering above the left or right edge of the slider.
Actual: The icon is a white hand symbol. Occasionally the timeline hides, the whole iframe is selected (blue-grayish overlay).
Expected: The icon is a black cross. Timeline does not hide itself, iframe is not selected.

Remarks: Doest not affect versions 1.3.1 and 1.4.0.