The group= attribute opens a new window only if no other window with the same group number is already displayed. When a window is opened and a user selects another window with the same group number, IPF swaps its image in the already opened window. To prevent this, use the viewport attribute; it always opens a window.
Suppose you have defined the following hypertext link to a window:
:link reftype=hd res=001.
vpx=25% vpy=bottom
vpcx=75% vpcy=100%
viewport group=2.
Guidance
:elink.
When this window is displayed, if the user selects the same hypertext link, the same window will open. You cannot control how many times the user will select a hypertext link. If you do not want another window opened each time the user selects the same hypertext link, use the group= attribute instead of the viewport attribute. This eliminates the potential for the user to open multiple windows containing the same information.