I exported the prefs of the 2nd workspace:
#Fri Mar 19 16:01:04 PDT 2010
file_export_version=3.0
@org.eclipse.jdt.launching=3.5.1.v20100108_r352
/instance/org.eclipse.jdt.launching/org.eclipse.jdt.launching.PREF_VM_XML=<?xml version\="1.0" encoding\="UTF-8"?>\r\n<vmSettings defaultVM\="57,org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType13,1268927419877">\r\n<vmType id\="org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType">\r\n<vm id\="1268927419877" javadocURL\="http\://java.sun.com/j2se/1.5.0/docs/api/" name\="jdk1.5.0_22" path\="C\:\\Program Files\\Java\\jdk1.5.0_22"/>\r\n</vmType>\r\n</vmSettings>\r\n
\!/=
Much less contents, so obviously the first export was an "export all".