I have file C:\Program Files\SlickEdit Pro 27.0.0 Beta1\macros\gnudef.e loaded.
Lines 0 (top-of-file) thru 83 are visible.
One mark in the overview bar, line 60 (defmain).
Single-click on the mark scrolls to make it visible.
So what is shift-click supposed to do?
If I repeatedly shift-click on this mark, the buffer scrolls up one line each time I click.
Repro:
go to top of file.
Click on the mark.
Line 60 scrolls to middle of screen (line 19 is top visible line).
Shift-Click on the mark.
Line 18 is now visible.
Shift-Click on the mark.
Line 17 is now visible.
Shift-Click on the mark.
Line 16 is now visible.