The "New Hypertext in Dialog" menu option sets a 
flag which is used by the OnHandleNewHypertextFile 
method of the HTDisplayBox component. This method 
is used to modify how clicks on links to new 
hypertext files are processed. In this case, the 
contents are placed as text in a display dialog 
before being placed on the main form. (This could 
be used to redirect the output of the jump to 
another component in an application.)

(Note: Assert methods normally are used to abort
all further processing of an action, while the
Handle Methods modify the processing. These
two methods can each be overridden in code by
direct assignment for Assert types and virtual
overriding for Handle types.)
