I, too, have found that trying to change the focus by double clicking in the Sibling window (using the default layout which has the Sibling window in the lower right quadrant) can cause TMG to close. The error messages are :
1st message: Visual Fox Pro has encountered a problem and needs to close.
Then: Fatal error: exception code C0000005@2008.01.24 10:41:47 pm Error log file: C:\windows\system32\vfp9rerr.log called from – tmgmain line 531 {c:\Program Files\The Master Genealogist v7\tmg\programs\tmgmain.prg c:\program files\the master genealogist v7\tmg7.exe}
If you open the error log file (using notepad or similar) you will find a list of when the problem occurred.
The problem appears to be inconsistant and random. It does not appear to be triggered by any particular situation or set of circumstances (other than double-clicking the sibling), but happens frequently enough to make me stop using that route to bring a sibling into focus.
I would hope the techies will find a solution soon!
Pat