Bug 305375 [ui] Many dialogs about unavailable sites
I20100309-0100 I ran a "Check for Updates" immediately after my machine had come out of standby. I don't think the wireless had fully connected yet, and the check for updates failed (fine). However, I got a half dozen nested dialogs about each of the sites that it could not find. They were all stacked on top of one another, and I had to dismiss each one individually. I would expect it to accumulate this into a single dialog rather than one dialog per repository.
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorContentService.java
}
	
	/**
	 * 
	 * 
	 * @param firstClassSource
	 * @param source
	 * @param element
	 */
	public void rememberContribution(INavigatorContentDescriptor source, INavigatorContentDescriptor firstClassSource, Object element) {
		/*
		 * We want to write to (overwrite) the contributionMemory only if we have never heard of the element before, or if the 
		 * element is coming from the same first class NCE, which means that the subsequent NCE is an override.  The override will
		 * take precedence over the originally contributing NCE.  However in the case of different first class NCEs, the first one 
		 * wins, so we don't update the contribution memory. 
		 */
		if (contributionMemory.get(element) == null || contributionMemoryFirstClass.get(element) == firstClassSource) {
			if (Policy.DEBUG_RESOLUTION)
				System.out.println("rememberContribution: " + Policy.getObjectString(element) + " source: " + source);  
			contributionMemory.put(element, source);
			contributionMemoryFirstClass.put(element, firstClassSource);
		}
	}
	
	/**
	 * Forget about the specified element
	 * 
	 * @param element
	 *            The element to forget.
	 */