Bug 97523 [Import/Export] Get overwrite prompt before no resources selected prompt
3.1 RC1 - File > Export > Archive - clear any selected resources - enter an archive file name where the file already exists - Finish - it prompts to overwrite the file; choose Yes - it says "There are no resources currently selected for export" (OK) Should get the "no resources" prompt first, and not bother with the second one. Should check the other export wizards too.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/wizards/datatransfer/WizardArchiveFileResourceImportPage1.java
*	Answer a boolean indicating whether the specified source currently exists
     *	and is valid (ie.- proper format)
     */
    protected boolean ensureSourceIsValid() {
    	if (ArchiveFileManipulations.isTarFile(sourceNameField.getText())) {
    		return ensureTarSourceIsValid();
    	}
    	return ensureZipSourceIsValid();
    }
    
    /**
     * The Finish button was pressed.  Try to do the required work now and answer
     * a boolean indicating success.  If <code>false</code> is returned then the
     * wizard will not close.
     *
     * @return boolean
     */
    public boolean finish() {
        if (!super.finish())
            return false;
        ArchiveFileManipulations.clearProviderCache(getContainer().getShell());
        return true;
    }
    /**
     * Returns a content provider for <code>FileSystemElement</code>s that returns 
     * only files as children.
     */
    protected ITreeContentProvider getFileProvider() {
        return new WorkbenchContentProvider() {
            public Object[] getChildren(Object o) {