And are you like me, annoyed when you compare and get the "Cannot open file C:\Documents and Settings\....\TFSTemp\...... The system cannot find the file specified." error?
The easy workaround is that you have to close WinMerge before calling it again from Visual Studio.
This is because the really popular string of switches out there (just google "winmerge visual studio") includes the /s switch.
The /s "limits WinMerge windows to a single instance," apparently by bringing up that annoying error. Not the most graceful way to do that.
Anyway, drop that /s switch. Visual Studio will be able to open multiple compare windows up for you. This might have other implications, but at least educate yourself as to what it does, and why that error above isn't really an error.
Here's the switch list I use:
/e /x /dl %6 /dr %7 %1 %2Reference this online manual doc for explanations on the switches.
"There is no off position on the genius switch. " -David Letterman