Bug 73984 Editing user library jar path after path change does not work [build path]
1) Create a directory containing jar file 2) Add this jar file to a new user library 3) Rename directory from 1) 4) Update the path to jar file in user libraries (select old jar reference, select new location in browser, open -> path is not updated, but old path is still used
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/UserLibraryPreferencePage.java
String lastPath= fLocationField.getText();
			if (lastPath.length() == 0 || !new File(lastPath).exists()) {
				lastPath= fSettings.get(PREF_LASTPATH);
			}
			if (lastPath != null) {
				dialog.setFileName(lastPath);
			}
			String fileName= dialog.open();
			if (fileName != null) {
				fSettings.put(PREF_LASTPATH, fileName);
				fLocationField.setText(fileName);
			}
		}
		private IStatus updateShownLibraries(IStatus status) {
			if (!status.isOK()) {
				fExportImportList.removeAllElements();
				fExportImportList.setEnabled(false);
				fLastFile= null;
			} else {
				File file= new File(fLocationField.getText());
				if (!file.equals(fLastFile)) {
					fLastFile= file;
					try {
						List elements= loadLibraries(file);
						fExportImportList.setElements(elements);
						fExportImportList.checkAll(true);
						fExportImportList.setEnabled(true);
						if (elements.isEmpty()) {
							return new StatusInfo(IStatus.ERROR, PreferencesMessages.getString("UserLibraryPreferencePage.LoadSaveDialog.error.empty")); 
						}