Visible area jumps around

[hansiglaser]

Describe the bug
For long Zim pages, i.e., where scrolling is needed to walk around, under certain circumstances, Zim randomly scrolls to parts of the page, which are far off the intended place. The cursor (for text entry) is at the correct place, but the scrolled (and visible) part is somewhere else.

This happens reproducably when switching between pages (using the breadcrumbs). It also sometimes happens when I select text with the mouse.

Expected behavior
Correct scroll bar position

Environment (please complete the following information):
Zim version 0.75.2 on Windows. The older version 0.69 did not have this problem.

[introt]

Duplicate of #1624