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/WizardFileSystemResourceImportPage1.java
setErrorMessage(getSourceConflictMessage());
            enableButtonGroup(false);
            return false;
        }
        enableButtonGroup(true);
        return true;
    }
    /**
     * Returns whether the source location conflicts
     * with the destination resource. This will occur if
     * the source is already under the destination.
     * 
     * @param sourcePath the path to check
     * @return <code>true</code> if there is a conflict, <code>false</code> if not
     */
    protected boolean sourceConflictsWithDestination(IPath sourcePath) {
        IContainer container = getSpecifiedContainer();
        if (container == null)
            return false;
        
        IPath destinationLocation = getSpecifiedContainer().getLocation();
        if (destinationLocation != null) {
            return destinationLocation.isPrefixOf(sourcePath);
        }
         
         
        return false;
    }
}