Bug 114512 [working sets] Package explorer should only allow working sets that have an updater installed
I20051101-0010 The package explorer started to support working sets different than the Java working set. However, the package explorer must ensure that an working set updater is installed otherwise it will end up showing stale/bogus content.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/workingsets/WorkingSetConfigurationDialog.java
updateButtonAvailability();
	}
	private List moveUp(List elements, List move) {
		int nElements= elements.size();
		List res= new ArrayList(nElements);
		Object floating= null;
		for (int i= 0; i < nElements; i++) {
			Object curr= elements.get(i);
			if (move.contains(curr)) {
				res.add(curr);
			} else {
				if (floating != null) {
					res.add(floating);
				}
				floating= curr;
			}
		}
		if (floating != null) {
			res.add(floating);
		}
		return res;
	}
	private List reverse(List p) {
		List reverse= new ArrayList(p.size());
		for (int i= p.size() - 1; i >= 0; i--) {
			reverse.add(p.get(i));
		}
		return reverse;
	}
	private boolean canMoveUp() {