Bug 293159 [Browser] Search for external browser in Preferences finds > 40 instances of firefox on Ubuntu 64bit, if started in /usr/bin
bundles/org.eclipse.ui.browser/src/org/eclipse/ui/internal/browser/WebBrowserPreferencePage.java
foundBrowsers.add(wc);
			
			if (file.isDirectory()) {
				if (monitor.isCanceled())
					return;
				subDirs.add(file);
			}
		}
		while (!subDirs.isEmpty()) {
			File subDir = (File) subDirs.remove(0);
			search(subDir, existingPaths, foundBrowsers, monitor);
			if (monitor.isCanceled()) {
				return;
			}
		}
	}
	/**
	 * Performs special processing when this page's Defaults button has been
	 * pressed.
	 */
	protected void performDefaults() {
		internal.setSelection(WebBrowserPreference
				.isDefaultUseInternalBrowser());
		external.setSelection(!WebBrowserPreference.
				isDefaultUseInternalBrowser());
		
		BrowserManager.getInstance().currentBrowser = null;
		BrowserManager.getInstance().setupDefaultBrowsers();
		tableViewer.refresh();