tabs scrambled in rekonq when desktop effects enabled

Binary package hint: rekonq

Using natty alpha3 with updates till t'day.
with enabled desktop effects (Nvidia card GT 240, nouveau driver, OpenGL in selection, but I don't think it really did that...), start rekonq, open a second tab and there go to any page. Close the second tab.
the tab background is not repainted and stays scrambled there, see screenshot.

All works clean with desktop effects disabled.
Please ask me for other details if you need to.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: rekonq 0.6.95-0ubuntu1
ProcVersionSignature: Ubuntu 2.6.38-7.39-generic 2.6.38
Uname: Linux 2.6.38-7-generic x86_64
Architecture: amd64
Date: Sun Mar 27 20:26:28 2011
InstallationMedia: Kubuntu 11.04 "Natty Narwhal" - Alpha amd64 (20110303)
ProcEnviron:
 LANGUAGE=
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: rekonq
UpgradeStatus: No upgrade log present (probably fresh install)