Selection of TextTable cells with triple-click selects adjacent cell on the right as well

Platform
Windows XP
Platform details
Bug occurs on both Linux and Windows in the Qt Textedit demo application (as well as our own) which makes it very unlikely that it depends platform specific details
Compilers
MSVC
Compiler details
Both gcc compiled versions on Linux and MSVC compiled versions on Windows show the problem
Subject
Selection of TextTable cells with triple-click selects adjacent cell on the right as well as the correct cell
Steps to reproduce / test case
Start textedit demo program.
Scroll down to text table.
Triple-click on any cell in any but the right-most column of the text table.
Observe selection of two cells, the triple-clicked one and its right neighbor.
The right neighbor should not be selected.

The problem occurs on both Linux (gcc) and Windows (MSVC). I don't have a current 4.6 build to test but older builds on the 4.6 branch show the problem too.