Starting UltraEdit from WinDbg

By setting follwoing env variable:
WINDBG_INVOKE_EDITOR=C:\PROGRA~1\ULTRAE~1\uedit32.exe %f/%l/1
{you might need to adapt the path}

You get the ability to open a source file from within windbg by simply right clicking on the source window header and then clicking "Edit this file..."

(this works also with other editors ;-) )