SOLVED! Slow scrolling line-by-line under GNOME

From: phayz <russelldicken....at.gmail.com>
Date: Tue, 11 Jan 2011 03:54:29 -0800 (PST)

In a discussion I started some time ago (link provided below), I
complained that Textadept was slower when I used the up and down arrow
keys to scroll in Textadept. What I found happening was that when I
held down the up or down arrow keys to scroll through the buffer, the
rate of refresh of the window's contents was slow and jumpy (depending
on the complexity of the lexer). When I did take my finger off the
arrow button, the scrolling would continue, because the update of the
window's contents hadn't been able to keep up with my requests. I ran
GNOME System Monitor to see if something was happening "behind the
scenes" and sure enough, when trying to scroll, the CPU load was
*VERY* heavy.

In trying to diagnose this I compared the behaviour of Textadept
against other text editors and found that scrolling in them was
faster. I tested editors such as gedit, gvim, medit and Juffed. Juffed
is written using the Qt toolkit and the QScintilla component. The
other text editors didn't have any performance problems when scrolling
through the *same* file. What made things even more difficult was that
soon after I raised the discussion on this topic, and got some very
useful replies, performance somehow improved. I recently found that
performance was again poor recently and again started on the journey
to enlightenment. :P

I thought it might be a problem with versions of Textadept but
changing versions didn't help. I had compositing enabled in the
default GNOME window manager - Metacity - so I turned this off but the
behaviour was the same. I also tried renaming my personal Textadept
configuration directory in case customisations were causing a problem.
Nothing seemed to help, so I was very frustrated. I finally decided to
test for this behaviour using another desktop environment - Xfce. The
behaviour didn't occur, which brightened my day. I thought I might
have to give up GNOME, which I didn't like the thought of. I then
tried changing my GNOME theme and bingo!, the behaviour stopped. I
tested this with Textadept open, switching to the problem theme, then
back to another, and the behaviour occurred when the problem theme was
enabled.

I have now switched "permanently" to another GNOME theme, and am happy
that my adventures with Textadept can continue. I seriously thought I
would have to switch to another text editor because of this problem.
I'm happy that it's solved and hope that this information might help
someone in the future. I have my fingers crossed that this problem is
permanently fixed.
Received on Tue 11 Jan 2011 - 06:54:29 EST

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