This is very similar to the already closed issue 212: "text added to nonvisible Text widget is shown" http://sourceforge.net/tracker/index.php?func=detail&aid=1446373&group_id=154155&atid=790646
The attached testcase script has two worker threads generating text data. Each thread has its own tab with an appuifw.Text component for the messages.
The display of the contents of the tabs are overlapping and mixed up even though only one of the tabs should be active and visible at one time.
Discovered on an N95 v30.0.015, using PyS60 1.4.4.