In F1.5 Schematic Editor, double-click on a net, press Attributes button, click on pull-down menu of Parameter Name, and it shows a list of Xilinx attributes (collapse, keep, noreduce, Loc...)
However, if the user re-installs Foundation, the list shows each parameter twice. If the user installs F1.5 three times, it shows each of them three times, etc.
解决方案
Each installation writes the same info and keeps repeating the same list into [Net Attributes] in c:\windows\aldec.ini.
A workaround is to edit aldec.ini so that [Net Attributes] section contains each parameter only once.