bug#35246: 26.2; Mouse wheel scrolling in GTK build sometimes scrolls the entire buffer

[Eli Zaretskii]

> From: Alex Gramiak <agrambot@gmail.com>
> Date: Fri, 12 Apr 2019 11:23:27 -0600
> 
> Occasionally, after first moving the mouse over the frame after it was
> iconified or unused for "a while", scrolling down in a buffer scrolls
> the entire buffer regardless of buffer length. During this scrolling,
> the GUI cursor changes to a busy (hourglass) cursor.
> 
> I unfortunately can not reproduce this issue reliably, which is why I
> held off on reporting this until now. I can cancel the scrolling when
> the cursor is an hourglass cursor, at which point the buffer is
> partially scrolled. I recall that debug-on-quit did not help here.

What does "C-h l" show after that?