Hi Enrico,
I'll try to explain in more detail:
What happens is: Geany presumably keeps the main window vertical coordinates of the functions, methods, classes, etc. (so that when you click on a function name in the side-bar, the main window scrolls to this function). When you change the font size, the total size of the main window changes too, and those coordinates are no longer correct.
Hi,
I have just noticed that changing the font size breaks the synchronisation between main source window and the sidebar with function names.
I don't know what you mean. Can you explain it in more detail, perhaps with a screenshot? Thanks.
Regards, Enrico