Hello,

several people have observed slow browser behavior in version 3.9, in
particular that browsers get slower the more of them you open [1].
Benchmarks showed that things were faster in 3.8 [2]. Jerome Peace
narrowed it down to 3.9 alpha, between 6684 and 6686. I have seen the
slowdownn disappear when switching off rounded window corners in my
3.9.1 dev image, see [1] for details.

So for now, if you want faster screen updates with multipe browsres
open, do not use rounded window corners:

  Preferences disable: #roundedWindowCorners.
thanks to everyone who helped with this.



[1] Mantis issue 0002084: Each overlaping browser slows down screen
updates considerably
    http://bugs.squeak.org/view.php?id=2084
[2] Thread "3.9 Browser speed" started by Andreas Raab,
    http://thread.gmane.org/gmane.comp.lang.smalltalk.squeak.general/108359