Just posted on MSDN Forum...

It's since three weeks that sometimes my local installation of Visual Studio .NET 2010 editor changes the source code lines adding several decimal digits when I recode the function or subroutine content (with the CTRL-K, CTRL-D shortcuts for example):

    CORRECT SOURCE

    yrif1 += 0.05 * _currentScale
    DrawScale(_currentScale, New Point2D(xrif1 + 0.2 * _currentScale, yrif1))

    ALTERED SOURCE

    yrif1 += 0.050000000000000003 * _currentScale
    DrawScale(_currentScale, New Point2D(xrif1 + 0.20000000000000001 * _currentScale, yrif1))

If I delete the less significant digits, the editor adds them again, when the cursors leaves the source code line. Do I need to uncheck Pretty listing (reformatting) of code in the Options > Text Editor > Basic > VB Specific panel? I would like to preserve such option, because it has always done a good job at reformatting the whole source code. I can't miss it.

It seems that behaviour started appearing in the last month, maybe some system patch. My system is a Windows 8.1 regular installation in Italian language and international settings are set as default.