fdo#40465 code pointers wanted (writer: page jumps when number of pages next to each other on screen changes)

Hi all,

I have been working on and off at bug fdo#40465.
The problem is that when the width of the window showing the document changes to an extend that the 
number of pages next to each other (the number of columns) changes, the visible page jumps.

If in a multi-page document that shows 2 pages next to each other
-you look at a page (row n when you regard all the pages arrayed in rows and columns);
-you change the width of the window (or zoom, or open/close a docked verticaltoolbar) so that the 
number of columns changes;
-the view is repainted and you will see that you still look at a page at row n. Only, as the number 
of columns has changed, that page no longer is the page you saw before the repaint.

(note: when the cursor is in view, zooming will not show this problem, becasue that part has been 
fixed)

Unfortunately, I haven't found the relevant code yet.
Can someone point me to the code where the page to be painted is calculated from the row/column 
position of the page?
All help will be very much appreciated.


Winfried