Bug 5092 Open type list - no longer works if ever cancelled during indexing
Build 205 Attempting to patch a binary project. I manually expanded its sources in a source folder, and then force a refresh from local. Then immediatly, I tried to open the type I wanted to patch, I got a dialog indicating that indexing was still in progress. I then cancelled my action (open type), and got a "No types available". Tried again later. The dialog came up again with "No types available", even though indexing was finished by then. It seems to have cached the empty list, and I remember this bug around 0.9.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/util/TypeCache.java
public void elementChanged(ElementChangedEvent event) {
			if (fgTypeList == null)
				return;
	
			IJavaElementDelta delta= event.getDelta();
			IJavaElement element= delta.getElement();
			int type= element.getElementType();
	
			if (type == IJavaElement.CLASS_FILE)
				return;
	
			processDelta(delta);
		}
	
		private boolean mustFlush(IJavaElementDelta delta) {
			if (delta.getKind() != IJavaElementDelta.CHANGED)
				return true;