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/WizardFileSystemResourceExportPage1.java
*	either pre-existed or this method was able to create it)
     *
     *	@return boolean
     */
    protected boolean ensureTargetIsValid(File targetDirectory) {
        if (targetDirectory.exists() && !targetDirectory.isDirectory()) {
            displayErrorDialog(DataTransferMessages.FileExport_directoryExists);
            giveFocusToDestination();
            return false;
        }
        return ensureDirectoryExists(targetDirectory);
    }
    /**
     *  Set up and execute the passed Operation.  Answer a boolean indicating success.
     *
     *  @return boolean
     */
    protected boolean executeExportOperation(FileSystemExportOperation op) {
        op.setCreateLeadupStructure(createDirectoryStructureButton
                .getSelection());
        op.setOverwriteFiles(overwriteExistingFilesCheckbox.getSelection());
        try {
            getContainer().run(true, true, op);
        } catch (InterruptedException e) {
            return false;
        } catch (InvocationTargetException e) {
            displayErrorDialog(e.getTargetException());
            return false;
        }
        IStatus status = op.getStatus();