In some scenarios it would appear that Xvfb isn't fully loaded or initialised by the time we try to launch Openbox causing it to fail to launch.
To ensure Xvfb is ready, we should wait a few moments after launching it before continuing.
The lack of a running window manager (as shown in the QPA debug output) was the reason why the KMyMoney reports-chart-test was flaky.

CCMAIL: thb@net-bembel.de