serial monitor hangs on long lines

If a large amount of data is received as one line, for example from
void setup(){Serial.begin(115200);}
void loop(){Serial.print("aaaaaaaaaaaaaaaaaaaaaa");}
with the serial monitor window open, both the serial monitor and the main IDE window become unresponsive after a few seconds.

They remain locked up even after stopping the data (by pressing the Arduino's reset button or unplugging the cable); the only way out I know is to force-close the IDE (losing any unsaved sketches), then reopen it and keep the serial monitor window closed until one has uploaded a different sketch.

This bug does NOT occur if similarly large amounts of data are received with regular newlines, e.g.
void setup(){Serial.begin(115200);}
void loop(){Serial.print("aaaaaaaaaaaaaaaaaaaaaa\n");}

(Tested with an Arduino Uno)

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: arduino 1:1.0+dfsg-9
ProcVersionSignature: Ubuntu 3.2.0-24.38-generic 3.2.16
Uname: Linux 3.2.0-24-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.0.1-0ubuntu7
Architecture: amd64
Date: Fri May 25 22:12:17 2012
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_GB:en
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: arduino
UpgradeStatus: Upgraded to precise on 2012-05-17 (8 days ago)