Check if a pointer points to a valid and running Word instance. The function does this by
trying to get the current selection of the Word instance and returns FALSE if it's NULL.
Usage
IsValidWrd(wrd = DescToolsOptions("lastWord"))
Arguments
wrd
the pointer to a word instance as created by GetNewWrd() or GetCurrWrd().
Default is the last created pointer stored in DescToolsOptions("lastWord").