The Case of the Three Second Delay (a.k.a What is SFTDDE?)

A while back I encountered an issue that forced me to become introduced to the DDE Launcher used by App-V (SFTDDE.)  A customer was encountering an issue where, no matter how much they tuned their terminal servers, even with pre-cached virtual applications; Office applications appeared to always have a three second delay when they double-clicked [...]