Simutrans Version: 102.2.1
Pak128
Problem: When using the mouse wheel or pageUp/pageDown to zoom, the center of the screen moves a little bit.
Proposal: When zooming, the center of the zoom should be (1) the middle of the window or (2) the mouse cursor.
Maybe this (1) is alread the case and some rounding error occurs.
You are really lucky ;), as my latest viewport patch also fixes this problem. When I wrote the viewport patch, the misalignment is far more obvious, as the viewports may have smaller sizes.
Nice coincidence :)
It works for me, too.
Further discussed here: Viewport patch (http://forum.simutrans.com/index.php?topic=4574.0)