[racket] drracket editor running too slow

From: Neil Van Dyke (neil at neilvandyke.org)
Date: Sun Mar 27 09:23:49 EDT 2011

I am *not* noticing this slow text selection problem on Debian (on which 
Ubuntu is based).

What I *am* noticing with Racket 5.1 on Debian Lenny is that 
progressively changing the DrRacket window layout with mouse drags 
(e.g., dragging to resize window, or dragging to move the sash between 
the Definitions and Interactions subwindows) is crazy-slow.

Looks like probably the common problem of keeping scheduling more 
re-layouts and repaints, even requests for the same are still pending.  
A telltale sign is when you pause the drag movement yet see multiple 
updates lagging behind the drag.  So you end up doing things hundreds(?) 
of times more than you have to.  I don't think that the speed of the 
individual relayouts is a factor.  Perhaps the code in Racket is not 
doing this, but some old version of a GTK-related library is being dumb.

To give you an idea of how slow... Just now, I used a mouse drag to 
resize a new DrRacket window vertically, from screen height to minimal 
height.  I then took my hand off the mouse and counted 7 seconds while 
the re-layouts and repaints caught up.  This is on a lightly-loaded 2GHz 
dual-core, with a simple GTK theme.


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